Hi. It's a quick beginner tutorial that answers a question from a new user called never Die on the Eevblog a forum and I Actually see this one quite a lot when they get in it. like it. one of these modern digital oscilloscopes.

For the first time, they read the datasheet. Oh, it's capable of going down of 1 millivolt per division. 1 division on the screen equals 1 millivolt. That's its lowest setting.

But when they they might take the thing out of a box or they're playing around with it and they might find that, Well, they can't get that set in. It only goes down to 10 millivolts per division. What's going on? Now if we take a look at the RAI Gold Es 1054 ZD r One of the most popular beginner oscilloscopes, you'll notice that it's got a vertical attenuation setting that goes anywhere from 1 millivolts per division all the way up to 10 volts per division. But sometimes what can happen? you either get the oscilloscope out of the box or you've been playing around with it and you might see that you can't actually get that value.

now. it can actually go to different readings. It can go up to a hundred volts like this. But more importantly, what the questioner asked is that he can only go down to ten millivolts per division.

And it doesn't matter whether has got his probe set to X 1 or X 10, it makes no difference. He can't get down to 1 millivolt per division that he wanted. He wanted to measure low level signals and he can't do it. So what's the problem here? Well, to an experienced oscilloscope user is really easy and obvious, but to be beginner, not really so much.

Let's have a look. If we actually go into our Channel 1 vertical menu here, then you'll notice that the probe setting is at times 10 and that is the problem. You just go in here, hit that and you go 2 times 1 because if you're using a times 1 probe, that's what you need to hit. And bingo.

It drops from 10 millivolts per division down to the speck of 1 millivolt per division. That's all it is. So for this volts per division set in here on your oscilloscope. to be correct, you must ensure that your probe setting here actually matches what you switch on here.

If you have it on X one, you use X 1 if you schoo and then switch two times ten. you have to go in here and switch at two times ten. Otherwise, your vertical reading here is not accurate at all. You're going to be an order of magnitude out.

Now, the important thing to remember here, and what confuses a lot of people is that you're the input to your oscilloscope. All those ranges. Those different selectable vertical ranges from 1 millivolt per division to 10 volts per division. They do not change.

They are fixed in the hardware. They've got physical amplifiers and attenuators in there to do that when you actually go in here and change this probe set in, all it's doing is it's a software function that just changes the multiplier down here. So if we put it 2 times 1, it's 1 millivolt. If we put it 2 times 10, it's like that if you've got a times 100 probe like a real high voltage probe, or if you've got a times 1000 probe for example.

you can go in here and the minimum you can go down to is 1 volt per division. and the highest you can go up to is an insane 10 kilovolts per division. Of course, this oscilloscope is not capable of 10 kilowatts per division. You need one of those real, proper, high-end professional high voltage pros, but it allows you to just to set that manually.

so it allows you to use any type of custom probe at all, including amplifiers as well. Like in the case of a typical two switchable x 1 x 10. Like this x one. of course the signal just goes straight through.

Times 10 is actually a misnomer. It's actually a divided by 10 probe. It's got a 9 mega resistor in here. one mega input impedance.

It actually divides your attenuator signal by a factor of 10. So the 10 times that actually shows on the probe here. That's like think of that as a reminder to set it to 10 times here on your probe setting on your menu. But if you had next to naught times 10 amplifier for example, you would set it to point 1 probe like that.

So you've actually got an an external amplifier that's amplifying your signal and you'll get the correct setting down here. It's all to do with software, nothing to do with the hardware range of the input here at all. And that's one of the limitations of cheap oscilloscopes like this. Rygar Diaz 1054 said it doesn't have what called Auto probe detection interface around here.

so the software in this oscilloscope does not know that you've changed that setting that you've added in a divided by ten divider. so it has no way of knowing that you flicked that switch. So you have to set this manually and it has this weird error message that says parameter limited here and that's just a little like work of the Rygel Oscilloscope. By the way, if you wanted to know that, it just means that you've reached the bottom limit of your set in here, so that's another question they asked.

it's nothing to worry about at all. I Don't like the way right? I'll do that. Higher end are more expensive oscilloscopes like this. Keysight 3000 X-series will actually have what's called an auto probe interface around the connector down here.

Now this will automatically detect the particular type of probe you got and automatically change that probe setting that x 1 x 10 or whatever particular type of probe you use. It'll auto detect it. So if you've got a match in probe for the oscilloscope here, you'll notice that it's got this little tiny pin in there which when we plug it into here will actually make contact with that gold ring around the outside there and this actually contains a resistor in it and it will actually be able to measure that you've hooked on a particular different type of probe and different probes can have different mechanisms. Some probes even are intelligent and they can use like an I squared C type thing and things like that.

a digital identification method. But watch this. Okay, it's currently set for a probe of one to one. Okay, this is Channel One, so it thinks there's because there's no probe attached.

It knows that it's going to be or it assumes it's going to be a X one probe. But if we plug in this match in probe, watch this change up here instantly. Bingo! Look times 10. But of course you have to use the proper matching probe for this particular type of oscilloscope.

If you try and use this Reigle oscilloscope probe, it doesn't have that pin on there, so if you actually go and plug that in, look, it just stays it one-to-one probe at X 1 Pro because it doesn't know that you've plugged in anything special. And if we get another advanced oscilloscope like this Tektronix 3000 series, you'll know It also comes with a pretty fancy looking pro. This is a one gigahertz one and once again, it's got that detection pin on there plus the circle actually surrounding. Now, as I mentioned before, this Tektronix probe is actually one of these smart probes.

It's actually got a communicator single pen communication system there. Even though there's all these extra pins around here. these are supplying for external power for different types of probes, but there's actually a chip in there that contains the serial number and you can actually transfer the settings for this particular probe from one channel to the next channel. So if we actually plug this in here, you'll notice that we're 1 millivolts per division.

We plug it in. This is a Times 10 probe. Of course, it doesn't actually tell you that on there, but all professional oscilloscope probes are times 10 only, so I'll explain that in a minute. Now, if you plug that in it, Go! It knows that it's a times 10 probe, so it goes up to 10 millivolts per division.

That's now our absolute minimum. We can't go any lower than that, but you'll notice that it's now got a serial number detected in here. It knows it's attenuation is times 10 and it actually tells you that here that you can actually store the compensation results for this particular probe and then it'll move it from channel to channel so you don't have to actually recompensate the probe every time you're moving your probes around. It's actually a terrific feature.

Now, although this is not guaranteed if we take our keysight probe here, it does have our detection pin and we actually plug this in. Will it actually change? Yes, it does. It changes to the 10 millivolt per division, so it knows you've plugged in a timestamp probe. So if we take our cheap ass Reigle probe which doesn't have the times 10 tip on there, then we plug that in and we're still at 1 millivolts per division.

So in that case, we have to actually go into here into our probe set up and we have to set our attenuation manually here. With there we go with the controller mode. We have to go up there a little bit fiddly 2 times 10 And this isn't just a trap for young players either. Even experienced engineers can get caught out like this if you're using these switchable times 1 times 10 probes.

It's so easy when you're just handling these or moving around on the bench to bump that that switch on there and and it's not really immediately visually obvious that it that there's anything wrong there. And it doesn't matter what oscilloscope you use this on, there is no way to actually detect that you've got times 1 or times 10 there unless you use a proper professional prior. but you'll notice that the professional probes never ever have this switchable times 1 times 10 on there. And there's a good reason for that.

And click here if you haven't seen it. I've done a separate video on why these probes are times 1 times 10 Pros: particularly in the times one position are actually quite poor unless you're using them to get the you know for really low level signals, they're actually their bandwidth and performance is quite poor in the times 1 position. So click here if you haven't seen that video. and the other thing the forum user asked about is why is there so much noise on the lowest 1 millivolt per division said it.

even if I disconnect the probes here, look, look, it's pretty horrible like that once again, I've done a video on that, so click here if you haven't seen that and I explain why this is the case noise floor on oscilloscopes and also why digital oscilloscopes can actually appear noisier than old school analog ones as well. I've got two videos on that, so click here if you haven't seen them all, they recommend it. So unless you're working on low level stuff I Don't recommend these switchable x 1 x 2m probes. They can be a real pain in the butt.

You can get easily caught out having the wrong scale factor here happens to professionals all the time. you just miss it. Whoa. Annoying.

anyway. I hope you found that useful if you did. Please give it a big thumbs up on YouTube cause that always helps a lot I think the thumbs in the other direction on Youtube. If you want discuss it, go on over to the Eevee blog forum.

Catch you next time you you.