Hi, welcome to the 555th Eev Blog episode. at least the official 555th video. Anyway, I've done like over 600 or something like that, but the official count of the videos seems to matter to some people. So yes, of course, we're going to look at the classic Triple 5 timer chip in the 555th episode.

Why? Because it's arguably the most famous chip of all time, and 555 just has that significance in electronics. Everyone's familiar with it. It's one of the first chips you play with when you're a hobbyist, when you're a young St or it used to be. now it's a bloody Arduino or something like that.

But it's still around and you know, until fairly recently, they still sold a billion of these things a year. I'm not sure what the current figure is, but that was like an early 2000s figure, but this chip has been around for so long, it's been used in thousands of different applications thanks to the various building blocks, a flexible nature of the building blocks, which we'll take a look at which hands Kem in, uh, you know, famously designed this chip and there's lots of info out there on how he designed it and uh, stuff like that, and it really is just a beautiful, beautiful design. So 555 Triple 5, as we call it here in Australia Let's not get started on the name, shall we? holds a very, uh, you know, sentimental place in electronics, so let's look at a discreet trip. 5 uh timer circuit today using discrete transistors I Got one of these evil mad scientist labs Uh, discret Triple 5 timer kits.

They call it the 35 kits. Anyway, it's worth playing around with and we'll go through. Um, the U basic, uh building. Uh, the basic block diagram of the triple 5 Tim and maybe some of the internal circuitry as well should be fun.

Let's go. And here's the kit from Evil Mad Scientist Lab The Three: FS Oh no, it's the Triple Five. Let's not go go through that again. We've debated that endlessly on the Ow.

Anyway, discreet Triple 5 Timer kit recreate one of the most classic, popular, and all around useful chips of all time. A faithful and functional transistor scale replica. Awesome. It's actually, um, a bit smaller than what I uh, imagined it would be.

maybe I'm um, I Got fooled by the uh, the Triple 5 timer stool. Anyway, this is really quite neat. They've got these. uh, really.

um, looks like C they're machined. They're not molded. They didn't I don't think they had the volume to go for. uh, machined.

but uh, looks like yeah, they've been stuck on there. look at right angles like that. So they've been machined out and like as a flat piece and then uh, an angle cut on there and then they've just been, uh, glued in place. So that's rather interesting.

and uh, here you go. We got some really nice instructions. Look at that. oh kid assembly instructions.

Beautiful. but of course we don't need that do we? n let's get straight into it. We've got ourselves a um, the bag of uh, screws and stuff big thumb screws to screw into there. and there's our board 555 timer.

Brilliant. Triple 5 and uh I hate that how they've U the PCB manufacturers just uh smacked on their um manufacturing code there. That just really pisses me off. Design by: Eric I'm not even going to try and pronounce that, but good on you Eric Awesome evil mad scientist.

Triple 5 timer Hit Fantastic! All the parts all through all don't need the instructions because they've got the values marked on the silk screen which is very nice so we'll jump straight into that and assemble it. Beauty Check this out though. they've included a card of Tada resistors. oh look at that isn't that brilliant.

All individually marked, Fantastic! And check out the lovely matte black solder mask on there. It's beautiful I got sick of uh, black solder mask when I was at Altium cuz Altium you did all their boards in Altium black and it had to be a certain type of black and uh, it was gloss black and it's pain in the ass I Hate gloss black? Um, but I do like the look of the matte black. the contrast with the white uh, silk screen on top overlay is just very nice indeed. Although the only problem with black is that you know it is quite hard to see the traces underneath.

You can kind of sort of see them under there like that. You know it's a bit more visible on the bottom there, but you know black isn't the best solda mask of any uh type if you're looking to see the tracks underneath. And considering that uh, this is a fully routed board like this, you may as well have gone in there with the uh route path and just routed out the little uh notch on there to uh signify pin one down here. But I love how they do have the pins numbered like that and you know the big screw in thumb screws.

Ah, it's just a beautiful kit really is. Well, I think the best feature of this is that the how they've divided the board into the functional blocks. we've got the threshold comparator, the trigger comparator, we've got the flip-flop and we've got the output. Beautiful.

And here we go: I'm uh, using my inverted uh Manfroto tripod here I actually tried using uh, that new manfroto um Flex arm with the super clamp up on the Shelf there but as I rocked the table um, the camera would just uh, you know, uh, sort of. you know, move back and rock back and forth and it wasn't that good at all. So I've had to revert to my inverted tripod Arrangement Anyway, um, this should be really easy to do. in fact.

uh, this will be just a single pass soldering thing where you just uh, place all the components first and then, uh, just you know, flip it over and do all the soldering all at once. Um, really, cuz there's you know. Uh, there's not a huge mixture of components, just resistors and uh, transistors. Very easy.

So uh, let's give it a bur, shall we? And we've got them all individually marked. Far too easy. and uh, we'll put this in. I Mean we do have MPN and PNP transistors so we have to be careful.

2N 394s and 23906 here. But uh, let's get, we' got a whole bunch. We've got individual resistors here or marked and then we've got 2, 4, 6, 7 of these. where are they? 4K So there's a whole bunch of 4K 7s in there, so let's get those in and I Do enjoy building kits.

It is quite therapeutic. I Don't get enough time to do it. Uh, one of the things you got to be careful of when you actually rip these things out of this. um, these uh, leader uh tape holders here.

I've mentioned this before, you can actually get gum on the end. These ones aren't uh bad at all. but uh, just be aware of that even with through hole stuff. If they got gum on the ends and they're a tight fit in the holes, when you actually uh push those in then um you know that can be a, uh a real issue.

it can get in the hole I mean you know it's it's not a it's not a huge deal, but just be aware of it. you can end up with a crappy uh solder joint on the top side. Not that it hugely matters, just a little note for young players there. So let's whack in all the 4K 7s.

I'm just bending these by hand of course I don't uh, really give too Hoots about the exact uh Bend radius and you know, I'm pretty good. Like you know, generally if you get this like a 400 mil spacing I think it is. you generally just bend them like that. you know you're going to be pretty close and they're just going to fall into place nicely.

Of course I have to orient the uh uh, the bands around all the right way otherwise the electrons will fall out. can't have that and uh 4K 7. Where's another 4K 7? There's another 4K 7 and uh, the 555 timer, of course, is famously supposedly using four 5K resistors in there in the uh divider string and uh, this one's obviously not. There's the uh uh, 4K uh 4K 7s instead being an E12 uh preferred value.

Not a uh, not a big deal, but that uh, sort of uh doesn't lead to the authenticity that the original triple 5 timer does. If you're a stickler for uh, your history on this thing, it normally contains the internal 5K resistors, but of course 5K is not a pervert value. Of course you can get 499 K or you could put two 10ks in parallel. um to give you a total resistance of 5K but uh, it's not quite the same thing.

Of course the chip. It's It's only a nominal value of course inside the chip. there we we go. All our 4K 7s are done far too easy.

820 Ohms, where's our 820? Ohms, people are probably screaming at me I can't see it I Got to look all over here there it is. Every resistor a winner and this is just a lovely, lovely kit I Highly recommend it. It's about uh, 35 bucks I think which is, uh, quite good value. Can you know there's not much in it? but uh, you know all the nice s legs and everything.

Um, makes it well worthwhile. Um, unfortunately there's no like uh, test points on the thing, but uh, test points. Of course you can just hook them onto the leaded resistors, but just not as nice as nice big uh test points on the thing. Uh, where are we? 1K we got 1K somewhere there we go and uh, this is just lovely 10K this is boring commentary I Mean people ask for me to build kits and stuff and they go.

oh why don't you do video of you're building kits? Well you know, look it's boring. What? What am I supposed to say? Well it's not boring for me I find it therapeutic. but for people watching I Don't see what uh value people would uh get out of watching me assemble kits. But hey, this is the 555th video.

It's the Triple 5 video. so you're going to have to endure me building the triple Five timer kit. Of course you do all your flat components first like your resistors so that you can actually flip them over. When you do solder them, they're all down at the one level.

Nothing worse than having a board that sort of, you know, rocks around and you're trying to solder it. so you solder up sort of each level. So on a typical board, you do all the resistors first, for example, through whole boards. Then you do say all of the Ic's cuz they're nice and flat and stuff like that.

so you kind of like do all those. and of course I put a little bend on the pins like that. that's fairly common just to hold them in place. Some people like the uh flip, you know stands, the soldering stands where you can actually just rotate.

You know, easily rotate these things hold them in clamps like this and uh well, yeah, I don't have one of those I just like, um, the feel of doing it by hand I don't like uh, clamps when I'm doing boards. not a huge fan of them I Can I can appreciate it for people who do it all day every day, so they're common in the production environment. For example, the good thing about these resistors? you probably don't have to bend the legs because they're um, a nice sort of snug fit in those holes. So really, you know I I don't have to bend those.

but sometimes if you got a board with loose, uh holes in there, oh like that one there. see that one? Hey there we go. No I spoke too soon. It did fall out there.

we go, but it doesn't matter. As I said, once you flipped it over, they're all going to sit down nice and flat like that. So that's the advantage of that last one. 100 ohms, 100 ohms There we go.

They've given us the exact number of resistors. This is a beautiful kit. All labeled value is labeled on the silk screen, so you don't have to reference the um, uh, schematic or anything like that. You can just Build It Up Now for the transistors.

Now the transistors are labeled 3904 um Npn 3906 PNP Just your uh, bog standard, um, signal transistor. Now these ones you don't want to, uh, pull out or anything like that. they're really annoying. So these ones You' go along with side Cutters and just chop them off.

So there we go. We'll do our 394s first and if we try and stick it in like that, it comes down and oh no, no, there we go. It fits in. That's not bad at all.

That gives it a nice snug fit and you'll find that the pins on the other side push together a little bit. These are a nice fit, especially for hand soldering. Um, because you just push them in and they sort of hold in place. So very, very nice.

Here we go: 394s and they've got the emit base collector marked on there. but of course. but um, oh oh, I've got them backwards. Oh I'm an idiot.

look at that look I've got two in backwards. I'm a total idiot. Look at this. There we go.

3904 There we go based on go I wasn't even watching I was too busy uh uh, checking to see if the damn thing worked. but I caught myself. You know that's the main thing. Mistakes happen, happens, folks.

can't avoid it Murphy will get you every time. I'll probably put one of these in backwards and people will be screaming at me as I'm soldering the thing that I've got it all wrong. and uh, so I assume that the pinout is correct because if they've goofed up their the flat on their silk screen, then well, the kit is hopeless. but I'm sure they haven't So nothing worse than having getting your silk screen wrong and then putting it in backwards and well, there is something wrong.

Worse than that is getting your uh, getting your footprint wrong, getting your pin outs wrong. Very common and happens all the time, especially with transistors which can be a real pain in the ass. Always double check your transistor. Footprints Folks Golden Rule Hopefully I Haven't put a 3904 into a 3906 position? I Don't think so.

I Just love the look of this kit. It's brilliant. How can you not like it? This is the matte black solder mask. Really really does the business on this board.

Don't always like it, but as I said, it's infinitely better than the glossy one. If I'm going to get black, always get matte black. glossy one is awful and oh man, it just irked me every time at out him and I was working it out here. Bloody gloss, black solder mask everywhere.

Unbelievable. All right. Yeah, the um. matte black, bloody, uh sorry gloss black solder mask got so sick of it and uh, and you couldn't see the tracers so it was a pain in the arh.

You know you got these really fine tracers all over your board and you're building and testing prototypes and sometimes you'd have to hack them and uh ah, it was just was awful. But hey, it was the company standard and it had to be the right type of gloss. black too. Oh man, those were the days.

that was a long time ago. Now that was uh 2 and 1 half years ago at least. And uh, time flies when you're doing a video blog. Let me tell you, I'm I've got to get one of these wrong I've got to goof it up on camera Murphy's going to get me cuz I'm not concentrating, you know I'm just I'm just cruising here I could almost do this blindfolded Stevie Wonder style.

So I hope you're enjoying this, folks. Those who asked me to assemble kits I'm assembling a kit with pointless commentary over the top I don't know. uh, don't know why. Anyway, I've um, what I've been doing at the moment I've actually been slowing down the videos um, trying to get to the triple 5 video cuz I didn't want to like cuz I had all these other videos like the um, make aair for example I've got like another couple of videos for the make aair, another three, or maybe even four videos for the make aair of interviews and stuff and I didn't want to release them cuz uh, that would have, um, screwed things up.

or at least if I adhere to my numbering system, I'll probably give it the same number, but then call it you know? video ABC or whatever. Part one, part two, part three I'll give it the same Eev blog number um, possibly. Yeah, it's always a toss up whether or not to you know, off topic kind of videos, whether or not to actually give them an Eev blog number. but I mostly do these days.

Today we're all done. That is fully assembled folks. Now that that's still bugging me that Bloody PCB manufacturer putting their process mark on there if you go to companies like uh PCB cart uh for example, they now they never used to give you the option they used to put this on and I used used to complain by default and I used to complain all the time to them about the boards I got and they finally listened and now they've got an option on their uh, shopping cart where you can say don't put any of that crap on my board thank you very much and uh, which is excellent but other manufacturers um, uh, other PCB suppliers don't seem to do that so it's a bit of a potluck. and when you're using a board as a front panel like this and it's important, you know I've had front panels come back and then all this gar manufacturer garbage just SP all over the front of your front panel, it's disgusting.

So oh hey, actually I probably. oops, that's silly. I should have solded my resistors. um that was dumb.

Yeah I goofed it folks I should have solded those resistors because I was mentioning before how you flip it over and it holds them all down? Well, they're not. Oh, that was dumb. See what happens when you're too busy talking and you're not? you know, do as I say not as I do So yeah, that's pretty embarrassing, but we're ready to solder. All right Here we go.

Let's uh, solder this sucker I'm using uh 6040 uh tin lead solder. There it is standard 60/40 stuff. ancient moldic core, uh stuff. .46 mm.

Really fine as I've mentioned in previous videos. I do recommend. Uh, you know your basic solders should be .5 mm or uh, less than that. so that's excellent.

So let's get in here. I don't use that lead free stuff. it's just it's just not worth a hassle really. And um, one of the issues here is going to as I said I should have uh uh, done all the resistors first and cut their legs off and then done the transistors.

but uh oops, too busy, uh yapping away not paying attention and um, but that's not a problem. so I'll just do all the resistor legs and cut them off. Now one of the issues here. I'm trying to.

it's not easy. usually I'd be flipping this board around all the uh place while I'm actually uh, soldering, but because I'm trying to keep it in a central location on the camera here. um, it does make it a bit more difficult. so this isn't my usual soldering style I'm afraid it's uh I get that in my soldering videos, the comments and things like that people are going: why did you do this? Why did you do that? And it's the you know it's not my usual, not quite my usual style so please forgive me I just don't want to, you know, move the board around everywhere I want to give some, uh, nice visual quality to the video? That's the idea.

Anyway, if my hand isn't in the way I don't know I'm not looking at the Uh screen at the moment. So one of the issues I've got to blow the soldo fumes away because if I use my solder um my Pace fume extractor then um, oops then I'm uh, going to. it's going to be too noisy cuz that thing is like a freaking jet engine. it's it's just absolutely awful.

I'm going to have to actually get some low noise uh fans. You know, the silent uh fans. you know, some 12vt ones or something like that, some big ones and just you know, stick some batteries on the bottom, maybe with a you know, couple of aa's and maybe boost the voltage up or something to power the fan and um, then uh, I could just have it next to the work and just blow the fumes away cuz of that's all that's required I'm choking on them. um just to blow the fumes Away really rather than uh, although I could have one on the other side so I could have I was possibly thinking maybe I'd have one one that there we go I think I got them all.

One that um, sits on this side here and blows across like that and you know, have another one which sits on the other side which actually sucks through and um, just have some carbon filter on that one. so sort of like I can position them uh, anywhere that would be uh, you know, kind of good. I could have a you know, a fan sitting here like this fan sitting here and it sort of blows across and sucks. and if they're relatively um, you know those silent type ones and I run them at a sort of a low enough speed cuz you don't need a huge airf flow to, uh, bring that across, then you know that's not a problem.

The Uh fume extractors aren't that great because you know they've got to run really fast and loud in order to suck the fumes uh through. CU they don't have a hood on top. the best Uh fume extractors I've used are of course the ones on a big snaking arm that you know come down and you can move them over your work and the fumes just go straight up and get sucked in. But when you've got a solder sucker that's on the side here trying to suck the fumes in, oh, it just, you know, it doesn't work really well.

So anyway, time to uh, trim these leads off and uh, let's have a look. Yes, this is going to be a long rambling video. As I've said in a previously, what you do with your Uh side Cutters is get in there but don't cut it flat like that. Actually give it a bit of a tilt like that and tilt it up.

Just gives it enough uh angle that you're not cutting into the shoulder joint. because you don't want to cut the shoulder joint, you want to cut the lead, not the joint. uh sorry. I've got to move this one around.

There's no there's no choice on this. Um, it makes it really difficult. So uh yeah, this is terribly exciting video folks. I Hope you're enjoying it, but anyway, some people wanted to see it and uh, me assembling a kit and well, this is what it's like.

It's not exciting at all and I just get to Waffle On and on and on. In fact, I've had to. um I've been sitting idle on this for a couple of days now. Oh no I missed one.

There we go I did miss one. Silly me, that always happens Murphy will'll ensure that you, uh, always miss aart don't always hold on to the leads by the way cuz uh, these things can fly right up into your eye. Not good. So there we go.

Let me finish that off and uh, here we go. all right now I can go around and of course because I did bend the leads on that. but um, just check that you know none of them are sticking out really ugly or anything like that. You know the uh visual aspect is kind of important and I think I yeah I did double check those Uh transistors and I had them in all the right way.

so I can start again anyway. I was saying that I had to. this solder in is actually uh, 3 or 4 days after the previous scene which was me actually assembling them in there because I didn't uh, have the time. I've had lots of family stuff on recently and I haven't done anything for uh, you know, 4 days or something like that.

So I've only just gotten back into it and at the moment I'm busy. um and I'm also busy working on my um, new microcurrent trying to get that sucker up and running. uh, which is a lot of work by the way, it's um, as I've discussed many times on the blog and the amp and other places. it's uh, you know, actually designing the circuit is uh, is not the and laying out the board for example is not not a huge part of it.

it's uh, the bill, materials, finding components in this case, really precise components and um, certain types of switches. I'm going to move this around certain types of uh, switch that I need and uh, getting stock of this sucker has not been easy. So I've had to, uh, actually commit myself to, uh, you know, several thousand volume of, uh, some parts um just to get them so that I'm not caught short cuz the last thing I want to do is run a crowdfunded campaign for example and find that I've you know got uh I'm over subscribed and then I can't deliver for 3 months because there's a you know, a huge lead time. Some of these parts are like, you know, 12 weeks Factory lead time so you know.

So if I didn't buy stock now I would have been uh I would have been screwed so you sort I sort of had to buy up in some cases I think all of the world's stock, these switches and uh and these resistors in order to uh in order to secure the uh success of my new microcurrent. Well and you know, just be might like that. you know no one wants to buy the thing and I'll be stuck with you know, a reel of a th000 parts at $4 each? you know and um, yes, one reel of Parts you know cost well over $4,000 It's just crazy and uh, which sounds like a lot but in the scheme of um, you know, um if you actually make make a th000 units you know it's uh and sell 1,000 units. it's not much at all.

it's all part of the manufacturing cost but when you got it up front that cost up front and you uh don't have any sales to at the moment to pay for that then uh you know can be a real pain in the ass. Oh sorry I haven't been checking the camera. has that been on camera? This is incredibly boring I should just uh, shoot video of me instead of the board. maybe yapping away.

Got to try and keep good posture too. I do pride myself on my posture I do try and keep excellent posture, but uh, you can find yourself lapsing here and there which isn't good anyway. So that's what I've been been working on for a while and that's why I haven't really been coming out with the videos and it's annoying me. and uh, of course this one has to be the 555th video so it's not like I can uh release cuz I got other videos I can release but I can't release them under the numbering scheme.

um otherwise I'd get to 555 and well, it wouldn't be the triple 5 timer video building this thing so that's no good. don't want that So I've had to slow down a bit and that's given me time to work on my microcurrent. I've been thinking about it for ages I changed Direction a couple of times, but I went back to what worked in the end and it's just a more precise version. There we go there is that's the entire board completed.

Holy crap there we go. I should actually trim off those uh leads. Of course, those transistor leads rather, uh, annoying. You got to trim those off.

But anyway, once again, same thing like that and then give it a tilt like that. so you're cutting into the leads and not the solder joint. that's a, a, uh, real beginner trap that one cut in into the solder joints. although sometimes you have to, you know you got to gr grind them down.

Sometimes of you know, um, ground boards down completely flat because you had to get it in some you know, tight enclos or something like that. or was some physical reason why you've had to make all the leads flatten and it had to be through hole instead of surface mount for example. And yeah, I' done that. uh, done that more than once that's for sure.

And uh, you know it, it works. There's nothing wrong with cutting into your solder. Gen I mean ultimately, it works. but you can, you know, get the stress fractures in there and stuff like that so you know it.

It's just not best practice to cut into the solar joint, but in practice, even though it's not best practice, it does. You know it. It does actually work. Um, but it just can't be counted on.

That's all. And uh, when you get a long-term a, um, you know, fracture like a a fracture in your solder joint that only shows up. you know, like as an intermittent long-term problem or something like that, then that can really ruin your day. You know it goes into a product, goes out the field and it only uh starts failing when it.

You know the joint heats up to a certain temperature in a certain environment or something like that, and you know you trace it back to uh, a solder joint and that's just crazy. But it happens and yeah, I've been caught with that before. but look at that. Tada Triple 5 timer board fully assembled.

That was really easy I don't know I wasn't timing that but doesn't take long at all. Um, it would have been uh, quicker if I didn't have the camera going and wasn't taking my time and just went all over the place. Sorry, that's just blurry. that's just going too quick cuz I can uh solder really quickly if I um so desire.

So there you go going to screw in the Uh terminals on that and make it look like a real triple 5 tier I Just noticed here their tips on uh how to sold I Got really nice little diagrams here I rather uh, like that, but they say um, but step two of course you know. step two: place a solder against The Joint that you wish to connect so and put the solder on F Touch the solder to the Joint first and then touch the ey into the solder joint for about 1 second. That's no, that's back to front. You need to put the iron onto the joint first and then the solder.

although You may have noticed, you know do as I say uh, do as I say not as I do you may have noticed that I sort of, you know, might have put them on at the same time when I was doing that. but um yeah, you're supposed to heat up the joint first, then apply the solder. That's how it works. That is the industry way to do it.

and then these funky looking IC legs just screw in there with these little uh cap head uh screws. Rather annoying that it's not Philips you got to go find your uh um, hex uh driver for that. but uh still. that looks really neat.

You know the black matches the black solder mask and I love capad screws. They're just really neat so that's just beautiful. And there's all the pin tails. Keep those folks.

they can come in real Handy Trust me always have a component drawer full of offcut pin tails. they're just great. Tada there's the finished article. isn't that cute I love it.

That's just great concept, brilliant. And the uh thumb screw terminals on here even got red and black for the Uh Power and the um five six other pins. uh, sorry for all the control signals. The only issue with this that immediately comes to mind as well.

Okay I've got to hook this damn thing up now. and I like the thumb screw terminals. but if I have to get you know a resistor from over here to over here, it's not going to reach I'm going to like it's not just like a breadboard where everything's nice and tight and all the components external components are designed to you know fit around the regular sized um IC on your breadboard and it doesn't do that. So you got to use like clip leads and wire and things goodness.

But gez, it's fun and you get to play around with the individual segments and probe stuff inside your triple 5. Brilliant and once again very detailed instructions on this thing. So you know if you're really after a beginner's kit. this one you know is really quite good in terms of you know, uh, soldering through whole stuff and just you know, getting a nice little uh, practical circuit to play around with and they've given you a suggested test circuit.

What? I Even like more is that they point to Colin Mitchell talking Electronics site for more stuff. definitely check out Cola Mitchell's Talking Electronics site and I've done some uh interviews with uh Colin Mitchell one of my heroes who taught me Electronics way back in the old days. So there you go and um, let's wire up this uh triple 5 lead blinker and well see if it blinks I've probably Goose something up probably won't work bloody Murphy Well of course astute viewers will know that My first mistake is think that pin 4 was ground. it's not on a triple 5 timer.

Pin 4 is reset. The triple 5 timer goes against the regular uh, you know, opposing side. Uh, pin out on there do I Just oh man. I was not thinking this was a triple five for some reason.

I Don't know. Jeez. I've KN the triple five timer pin out for you know, 30 years or more. but you know, still screw it up because I'm too busy yapping away I'm just not paying attention.

and of course I don't follow instructions. There we go. Now we're ready to go. So here we have it all wired up.

And yes, it's a bit messy to actually use it in this configuration. Yes, you can get resistors directly from point to point like that. So the classic Aable configuration like this. you do need you know, a couple of wires coming around here I didn't want them going over the top.

Uh, like that because we're going to be uh, probing stuff on here. um I've got a 3.3 Vol uh, 3.3 mic cap 450 volts I think it'll do it anyway. that's what I got out of my junk bin I got a jumbo lead as well. considering that this is a jumbo triple 5 and here it is classic.

Um, a stable configuration for the Triple 5. uh timer. It does warn you though. it's not a direct replacement.

If VCC is greater than 6.5 do not connect reset directly through cuz normally the uh reset pin four would be connected directly to pin 8 up here. but it says you got to put 100K in series so that's a limitation so it's not a direct functional equivalent. Although they recommend uh, they say that it should be in most uh uh uses and configurations, but that is one small trap there. So we got 100K pulled up there and we should blink our lead it I don't know a Herz or two.

something like that. Haven't done the calculation, but flick the switch and uh, I've got it powered from 9 volts. Let's have a look. it's on.

hey hey, it's blinking. it's blinker. We have a blinker there we go. Works A treat.

Um, we obviously don't need anything on the uh control voltage really. cuz it, you know it doesn't matter a rat's ass. That's just basically some um, internal, uh, bypassing and stuff. So really, we're looking pretty.

Look at that. it works. Bobby Desler. Oh, and by the way, this isn't a plastic, it's a hard cell PVC foam so you can actually get in there and uh, Dent that if you really want to.

but that's really neat stuff. You can make some cool stuff out of that. It's lightweight and rigid, but uh, easy to cut and mold. The uh model making industry use it.

uh, extensive. You know the props, industry and model making uh type stuff. use this hard sell PVC phone pretty extensively. Now here is where we're going to get a bit messy, but stick with me and apologies at the start.

I haven't uh, thought this through. So I'm a kind of winging this, but we're going to have a look at the triple 5 circuit diagram here. Now this is one of the more disappointing things with. well, the most disappointing thing with the kit is that it's designed to, you know, allow you to play with a an A transistor based replica of a Triple 5 timer and it neatly divides them into the threshold comparative, the trigger comparative, the flip-flop and the output and the reset and all that sort of stuff.

But what it doesn't do is give you a circuit description of how any of this works and I think that's greatly lacking for people who want to. It's almost defeats the uh purpose of the kit really. cuz who wants to play around with the outside? You want to get in there of your scope and look at waveforms and do things like that so it really, you know would pay for them to have some sort of, you know, deep uh description or you know, at least some sort of description of how the arrangement Works in here anyway. I'm going to uh, have a crack at it and U do a few notes if I may.

Now the first thing I notice is that uh, this these three resistors here aren't part of this trigger comparator. So I'm going to draw a dash line down there like that because these I and they should be by the way 5K Because Well, 555 Triple 5 Now of course. um. hands C in I Think has Um actually said that? No, that has nothing.

That's not why it was named uh that because it actually had um, you know the five nominal 5K resistors in there. The number was just a, you know, next in their sequence or something like that. I Don't know. it's got nothing to do with it, but by coincidence, it does have 555 in there and that's just a resistor divider in there to generate the Uh threshold voltages.

And of course, the Uh control voltage pin is directly connected to one of those uh Taps here. Now what I've got is basically the same diagram that's on my trip timer shirt. This is the typical internal block diagram of the triple 5 timer, and we'll see how these modules relate to these items in here. Like the threshold comparator.

There's the comparator of course, connected to the threshold pin. We got our trigger comparator sometimes called the upper and the lower Uh comparators. This is the that goes to the trigger pin in there. Um, and there's the 555k resistors in there.

They set the Uh threshold values for those trigger comparators. Then we've got ourselves a flip FP flop here, which we'll take a look at. Then we've got our output driver here, and then our discharge um pin over here and the reset is tied into the flip-flop So we're going to, uh, come back to this Um periodically. But let's uh, start out with, say, the threshold comparator over here and see what we've got.

Now in, the threshold comparator looks a bit complicated. They got all these transistors connected in weird and wonderful ways like this, but it breaks down fairly simply and let me briefly explain what we've got here. Basically our two inputs to our comparator. One here, which is the threshold pin, the other comes from the voltage tap on our 555.

um, uh, resistor ladder there. So these are the two inputs to our comparator. just like you'd get a regular uh comparator, you know, Lm311. You've got your positive and your negative input there, and this is a, um, typical Arrangement What it is is basically a differential pair amplifier and uh, but it's working as a comparator cuz there's no external feedback to make it work as an amplifier.

and usually these are pretty crude amplifiers. but they do work work uh, reasonably well as comparators, but not on their own. You've got to have some current sources, which we've got up here that just make them a bit less sucky as comparativ. So uh, what we've got here actually is these two transistors here and here.

There's nothing unusual about these Arrangements at all. that's just a Darlington pair. So you know if you're familiar, should be familiar with your Darlington transistor pair. There it is.

So they've just got extra Uh gain in there so that the Um input current on the pins is very small for a particular gain. so they're just increasing the gain with a pair of Darlington. No issue at all, no magic going on there whatsoever. Once again, there's nothing tricky going on up the top here.

um at all. Really, it's a standard build building block component called a current mirror and that's what this these Arrangements of these two transistors um does here. Now what we've actually got here okay, is this You see how the the Uh base is connected to the collector here on this one and this one. well basically what that is acting as is a diode.

So essentially what this thing is here is just a diode connected like like that and this arrangement I won't go into how current mirrors work, but basically that's a you know I could do it like a fundamentals Friday video on that. But basically the current flowing in there and down there like that is going to be equal. so that's all there is to it. And likewise, on this side, over here, they've got exactly the same thing.

this Arrangement is going to be a diode like that and by current Mirror action we'll call it. The current flowing down here is equal to the current flowing down here and that's all you got. So they've got two constant current generators. Sometimes they'll have the constant current uh Source down in the bottom uh, resistor down here.

They'll replace that with constant current. but what they've got it is the constant current up the top. and I won't go into the pros and cons of various Arrangements but that's what they've decided to do in this Arrangement So constant current feeding this so it acts as a, you know, a decent uh comparator and then the output in this case is tapped off here. and this is one of our outputs.

In fact, that is the reset output coming out of our comparator into here. so we can go over here and label that input r on our flip-flop there. So that's all there is to it. so that is not too dissimilar to just a regular comparator chip that you would buy off the shelf.

Now over here in the trigger comparator, it's essentially uh, the same function. It's just a comparator because look, it's it's. really no different except uh, we've got our external input going to the negative input, but they've decided to configure this transistor Arrangement differently using P&P transistors down here instead of Npn. And actually, this is a more typical uh comparator Arrangement you'll find in commercial comparator chips which you can just, uh, buy off the, but it essentially works just the same.

We've got a constant current going down here by virtue of this transistor over here. Once again, we've got our current current mirror. Arrangement This is actually, once again, we've got ourselves a diode in there, so the current um flowing down here is going to be a constant current setting. the bias for this comparator down here very simple and once again, we've got another Darlington arrangement there as well.

but with that Pnps instead of MPN And then we've got our output being tapped off here. and so that becomes our set input to our. and there's the output of the comparator. That's the set input going into our flip-flop block over here.

So there you go. We got our two comparators there with the R and S inputs to the flipflops. Too easy. This one here is not actually one of, uh, part of this functional block.

Arrangement They just got like a jewel. Uh current sourcing Arrangement Here that's actually I Think that's probably clever Hans has probably uh, done a trick or two in there to, uh, save the odd transistor I Think that could be neat that could. Um, you could go into more detailed analysis of uh, why that is done. but as you can see, it's pretty much following this Arrangement we've got here.

So as I said, this one, uh, helps provide constant current to both of these points down here. So we've got, basically, let's have a look at our flip-flop Arrangement Now now, technically, it's probably not correct cuz it's not really a clocked uh flip-flop As such, the more correct term would be an RS uh latch and uh, that it should have uh, four, uh, two inputs, two output sorry, three inputs and two outputs reset pin We've already got our RNs here and of course our reset arrange M comes from over here into there. So there it is. So that's our uh well RS So we'll call that Rst reset there going into our flip-flop and these here are our so that's our Q output and that's our not Q output from our flip-flop block.

So how does this RS flip flop block work? Well, it's rather interesting now. a normal uh RS you know Tex book RS uh, latch like this made up of two nor Gates like this cross coupled nor Gates And of course you might have a uh, a third input here for your reset. Um, you know, external reset pin. but um, that is not what we find here because we have a look at a typical old school data sheet for a Norgate I mean look at how many transistors we' got.

We basically got an inverter and some Nang Gates and inverts the output and that's you know basically how it does it now you um in fact, often you will see this configuration in a trip 5 timer. uh you know block diagram. Instead of just showing it like this, they might actually show these cross coupled RS flipflops. But look at how many transistors we got to implement and that's just for one.

Norgate So we'd have to have two of those in all of this up here and we don't have that. We just got some constant constant current. uh Source up here. that's pretty much it.

So these transistors down here, we don't have enough to implement this classic. Arrangement Well, we don't have to cuz what they've done is what Hans has done is uh, implemented the classic two transistor. Arrangement Like this: RS it does exactly the same job and you'll notice it may not look like the same as this, but it actually is. Follow with me here.

let's assume that this is the well we know. This is the set input here. Okay, so this is the base of the set transistor. here.

This is our set transistor and that then feeds back via a resistor here back to the base of the reset transistor. There's our reset input. So this is our set transistor down here. This is our reset transistor and you'll notice it is cross coupled back here.

It is cross coupled back there to there, but there's no resistor in there. Where is that resistor? Well, we don't need it because we've got that constant current Source coming from over here so we don't need that series resistor so we're not going to blow our transistor. It already is limited by the internal constant current Arrangements of this chip. and it's very common for chips like this to have constant current generators everywhere.

Like a typical compara might have three or four constant current generators in it all over the place and things like that. So that's the way they've got away with directly connecting the transistor in there like that. And by the way, this, um, this particular Uh circuit is taken directly from the original Signetics Triple 5 time data sheet, which is fantastic, which I was linking down below. They got some excellent drawings in there, as in hand sketched, uh, little cartoony drawings.

Fantastic. But anyway, that was a little aside. We've got this classic Arrangement using these two transistors here. Very minimalist, uh design.

Fantastic. They don't even need that resistor in there. And it's um, and you once again notice this: Arrangement Here is our diode. so we've got effectively a diode like that.

And that's what allows us to feed this external reset into basically the Uh same Arrangement as the into the Uh reset flip-flop which then is buffered from the output of here. So we've taken, we basically taken the output from our reset. There it is. we're taking our output from here like this from our reset uh uh, transistor sorry not reset flip-flop reset transistor and that is then driving that through this constant current generator here and that is driving our complimentary outputs of Q and not Q That's all there is to it.

It's a very clever implementation of a basic RS latch. I Really like it. And then from our Q and Notq, we can see how these Drive the output buffer and the Uh discharge transistor down. Here here's the output buffer uh block and you can see that it is driven by the Q output there.

and basically that's a totem polar. Arrangement Once again, we have ourselves a diode in there like that and so that is just a buffer to drive this totem top standard to pole output like that. Too easy. So these are all just, you know.

Standard Building Blocks So when you know your circuit building blocks like your totem pole output like your Diod from the transistor, you got your Darington pairs, You've got your current mirrors, and you know it all. Sort of starts to make sense and come together this convoluted circuit diagram. once again, here is the uh, um, Notq output coming via a resist resistor. There There it is, straight into the uh, open collector output discharge transistor.

Too easy. So there you go. I Hope you found that uh, brief walkthrough somewhat interesting. and of course you could play with this to your heart's content.

And that's the beauty of this kit. You can get in there. You can see what the current Mir mirrors are doing, You can see how the Um RS latch is working, see how the totem pole output works, the comparators. everything like that at the transistor level.

It's brilliant. And it's a shame that this kit doesn't come with a really detailed circuit explanation of how this works cuz it's a great learning tool. I think for discrete transistor design and yes, I've probably goofed something up in there I haven't really thought about this in detail. There's probably a few nice little uh tricks in there that um H's put in to sort of optimize this and lower the transistor count and get the Uh performance required.

And you know stuff like that. So not really going to go into uh, deep analysis of this thing. Um, by the way, the LT Spice Circuit simulator uh, the free one from Uh linear Tech Um comes with a transistor level Tri 5 timer. um.

circuit. It's all. It's not too dissimilar to this. it is.

you know, functionally identical to this. It's drawn a bit different, of course, uses the transistors in a different sort of uh Arrangement, but it allows you to play around with a triple 5 timer in a circuit simulator and that's one of the examples that come with it. So I highly recommend you download that have a play with it although I haven't played around with it myself. so I don't know how it performs and simulates, but I do know it's there.

All right. let's take a look at some external scope waveforms or external to the Chip And We basically following our standard uh got our Aable circuit built as showing here. Now the yellow waveform is Pin Six, which is the Uh threshold comparator pin. the green waveform there is Pin 7even which is the discharge, open collector discharge output, and the blue waveform of course is our output voltage.

And uh, you'll notice that. Well, there's our output voltage. You can see the blue waveform like that and that's that's what. Uh, when it goes high, of course it's switching on our lead because we've got it.

Uh, driving the lead via the anode there. Now if we have a look at our yellow waveform here, the charging. That's the Uh Main capacitor. That's the one or 3.3 microfarad capacitor charging up via the 100K resistors there.

So 200k in series via 1 microfarad and that's the charging waveform. So you can use your formulas to calculate how long that's going to take to Uh charge up and then it is when it reaches the threshold voltage. If we have a look at our Um internal block diagram of a triple 5 the comparator. Because of the 555 K resistors in there, it's 2/3 The threshold comparator is 2/3 of the supply voltage.

In this case, the supply voltage is 9 volts. So our threshold voltage is going to be 6 Vols and is it? here's ground? We're at 2 vs per division 2 4 6. It switches at exactly that 6V uh threshold limit and then once that happens, our discharge pin kicks in. So our Noq output um turns on the discharge uh transistor which then discharges the current.

Please excuse the crudity of all this. Um, then it discharges the charged 1 microfarad capacitor which is currently at 6 Vols and discharges it through the 100K resistor down to ground like that And that's exactly what we're seeing there. It's discharging back down. It's taking half the time that it took to charge up because it's only going through 100K resistor instead of the 200k And and of course then our uh trigger comparator down in here is measuring that value uh at one, because of the 55k resistor divider in there, it's 1/3 of the supply voltage or 3 volts.

and Bingo! Look, it discharges from 6 Vols down to 3 volts and then the cycle starts again. and of course I'm preaching to converted. Most of you know about a standard Tri 5 timer operation. So there it is, it's all confirmed and verified Works A treat.

Now, what we can do with our fourth channel? the pink channel here which I'm touching with my finger. We can probe around the circuit here and have a look at some of the waveforms, shall we? Let's uh, take a look at our um uh reset input of our RS uh of our flip-flop latch here. so that's the collector of Q6 and luckily they have labeled Em base collector on the overlay and there it it is. You can see that out output there because it's It's actually quite small.

That's uh, 500 MTS per division. So it's about 600 MTS one diode drop so that. but that is basically switching that constant current Source off and on there. which goes then into um, our flip-flop over here and let's have a look at our set one that should be much lower.

We should be looking at Diod drop switching there. So look at base of Q15 which is there. It is base of Q15 and there we go. We're not actually getting a pulse.

uh well. well we're getting just a pulse on that. Check that out. Oh no.

there we go my trigger. Point's a bit off, but yeah, you can see we're just getting that little Um set pulse down in there. Just once again, that's only a single diode drop. There it is 500 Ms per division single d drop just to switch that transistor back on and change States Then we can have a look at things like this.

Uh, constant current output here which will be switching. Of course that's our drive, the buffer drive going into our Uh, Q and Knar output. So let's have a look at the Uh Collector of Q19 A There we go, Collector of Q9a and there we go. It's switching.

Now if we have a look at our Q output here, let's have a look at that. that is Uh, the collector of Q20? Yeah, where is it Met base collector? no collector? There it is and that is our Uh QQ output going into our final output buff stage. nice and squared up. Huge voltage there.

almost full swing and now not Q Output here is once again only small. We're only talking. you know, a Diod drop sort of level. There There we go, we can have a look at things like you know, the constant current output here for example of the Q9.

So let's take a look at the collector of Q9 there and you'll see that that that was just some contact bounce there and you'll see that that is basically just a steady state voltage steady state current. Of course we're only looking at the voltage here, but basically that's going to be a constant current Source coming out of there to bias all of our uh, trigger comparative circuitry down here. So you can just probe around the circuit here to your heart's content and figure out exactly what's going on. And maybe, uh, compare it with the LT uh spice simulation for example.

So it's a really handy kit to figure out how this sort of stuff works. Of course there's going to be, you know, uh, processed technology differences between a discrete transistor design like this and the actual manufactured triple 5 timer IC of course, but you know, functionality wise, it it's going to operate fairly similar Now if we actually probe the outputs of our set and reset transistors here inside our latch, so we'll probe the collectors there. you'll see that they'll be opposite polarities both single diode Junctions So let's have a look at the set q15, the collector of that and you'll notice how now that is there you go. It's positive wh positive going while the output is low and we should get the opposite on Q16 down here, the collector of that one and we do.

There we go. It is low when the output is low, so there you go. I Hope you found that interesting if you're still with me after what's have been an hour or so. Oh, we're well done sticking in there.

but uh yeah, I Was going to do a few more things for this uh triple 5 timer video but oh, you know things happen and H they just don't get done. Maybe for 5.56 I Don't know. but anyway, um if you enjoyed it, please give it a big thumbs up and if you want to discuss it, jump on over to the EV blog Forum Catch you next time. Good on your hands.

What a beauty.