Hi, I'm going to show you a neat little feature in multimeters you probably weren't aware of. Now, most multimeters these days have a capacitance mode either a single on the dial like that, or a switch through um, typically on the Ohms range like this and you can measure uh, your cap like that. No worries. Okay, we've got our 10 Nano Farad standard capacitor here and it measures that.

No worries, except for this one. I don't know why this fluke is out, but anyway, they have reasonable capacitance measurement in them. It's not great, it's usually only like a couple of percent accuracy at best, but it's quite handy. Not as good of course as a proper Lcr meter where you can, um, select, uh, the different Uh test frequencies, but you can also measure not only capacitance, but inductance um as well and resistance and Esr and quality factor and dissipation factor and all sorts of stuff that you get with a nice Lcr meter.

Now there's only a few multimeters on the market that will actually have inductance measurement built into them, and they're They're pretty rare, but a little known feature of Uh Multimeters is that they actually test at, well, not um, specific, fixed frequencies like a good Lcr meter does. This one can measure 100 hertz, 121 kilohertz, 10 Kilohertz, and 100 kilohertz. But multimeters also test at frequency as well, which means you might be able to press them into service for measuring inductors as well. Let me show you so we'll have a look at the actual waveform, the test signal that's actually being used now, of course, For an Lcr meter, we're getting of course, a perfect sine wave like this at the perfect one kilohertz that we select.

And of course, at 10 kilohertz and we can go to 100 kilohertz and we can test down at 100 Hertz if we want to. There you go. So a perfect sine wave at a specific set frequency is what you get with proper Lcr meters, but if we swap that over to a multimeter in this case, got the 121gw, you can see that it's actually got a triangular shaped waveform here. and that is at 100, you know, just a little bit over a hundred hertz here.

And if we change the capacitance, it's actually the test frequency is going to vary with, uh, the capacitance. But not all meters work identically like this. And then if we try the fluke here, you can see that that's once again the same one nano Farad, but it's higher frequency. Again, it's testing at 4.3 kilohertz.

it's not quite a uh, triangle wave there. And then if we change the capacitance, you can see that the test frequency uh, changes with the capacitance there. And then if we try the Uni-t 61e. uh.

Plus here you can see, um, that that's a 142 Hertz, but it doesn't really change frequency at all with the capacitance that we're actually testing. So you know every multimeter uses its own little secret source. Every multimeter chipset's different. Everything like that.

So you can probe your multimeter and have a look for yourself. And they'll have different test signal levels. and they'll have different biases and everything else. But anyway, I'm just showing you that they all work uh, differently.

Now you should know. Uh, your capacitive uh, impedance formula Xc is one on two times Pi times, F times C. and then they can calculate uh, the capacitance. You can rearrange that to calculate the capacitance.

Well, uh. you should also know that the Uh impedance formula for an inductor is exactly the same as that, except it's not the reciprocal. It's just two times Pi times F times l. So what you can actually do because there is actually a frequency component in there? You can actually press your multimeter into service to measure inductors.

It's not perfect, but you can actually do it. And this one over or reciprocal measurement mode as it's called, is used on some multimeters like the Fluke 87.5 here for measuring large value resistors. It's actually got a Nano Siemens mode. so I'm measuring a 10 mega ohm resistor at the moment.

but we can actually go into Nano Siemens mode here. and if we hook on, this is a 10 gig ohm resistor and it's a bit touchy because it's really high value. We can actually measure that and it's point One One or point N says point One Nano Siemens and if you get the reciprocal of that one on, point One Nano gives you the 10 gig. Ohms.

And that's how the Nano Siemens mode works. Well, You can kind of sort of do a similar thing with inductors on your capacitance range on your multimeters. It's not terrific, but you can get it to work and you can see serious changes in frequency as I change the range on the meter here. uh, frequency and amplitudes and maybe offsets as well and stuff.

So yeah, um, each meter is going to be quite different, but there you go. Let's go to Dave Calc here and I'll show you how it's all going to work. It's not that intuitive and it's all uh range based as well because as I showed, the different ranges have different uh frequencies and whatnot. so it depends on the range you're on.

So one one milli Henry inductor is actually going to read one millifarad if you've got it on or it should in theory. Um, if you've got it on the milli farad range. but it gets weird for the other ones gets a bit non-intuitive 2.2 milli what you've got to do, you've got to take out the milli there. Okay, so assuming you're on the milli range on your meter that matches this range like this that the inductor you're trying to measure, then it's at 2.2 You invert 2.2 on a calculator and you get 0.55 and then you just keep the units the same.

So 2.2 millihenries should in theory read as 0.45 millifarads or 455 microfarads and so on all the way down. And if you're on Micro Henry's range, then you need to be on Micro Farad's range over here. and you may have to use a thousand of, uh, multiple if you're on the wrong range and you get the reading here. Anyway, let's have a s Let's see if this actually works for you.

I'll just, uh, auto arrange it here. Hopefully we'll get the right range. I'm on 150 Milli Henry's here. Will it? actually? Will It actually work? Uh, 150 millihenries? Uh, we should be getting six 6.6 micro farads, a 6.1 So the lower that is, the higher.

Um, it's going to be in the inductance so that's reading slightly over. We can get the confuser out. so we want to convert this to millifarads to match the range. So 6182 like this and you invert that and we get a hundred and sixty one millihenries.

Um, there you go. That's not too far off. so let's see what the Unity reads. Six Point One Eight will get in.

Is it going to do the same range? Six Point Three One? There you go. That's not too shabby at all. And well, let's choose say 47 Millie Henry's Uh, what do we expect? Uh 21 Mike We're getting Ah 23 Mike There you go and we can swap that back. Come on, you can do it.

23.5 That's good enough for Australia. That gives you a pretty decent indication. Let's try: 10 Milli 91.3 Okay, we expected a hundred there. Well, our inductor might be a little bit out.

90.3 There you go. That's all right. And if we compare the actual Uh values here with the proper Lcr meter, I'm measuring at one Kilohertz here. the 6.8 Milli Henry is actually uh, 7.3 and the 10 Milli Henry's actually.

well, that's pretty close to uh, bang on 10. And 47 Milli is uh, 50.8 So you know there's some errors in there. But man, there you go. 106.

But you know it's nothing doing really. All right. Let's try a 220 Micro Henry. uh, Smd inductor here.

Let's give it a bowl with our Lcr meter. First, there you go. 233 Micro Henrys. All right.

let's try the same thing with our 121 Gw and get on there, you bastard. Ah, come on. easier to probe on the bottom. I think there we go.

Four point left. Let's call it 4.9 Nanofarads. Get the confuser out here. 4.9 Um, we leave the units off so we invert that.

that'd be 204 micro because you've got to shift it back that way that's not too far off, Is it? That's all right. Not too shabby. Well try the Unity 4.84 Let's try the Fluke 87 here. 5.3 That puts it, uh, a bit lower.

So leave it up to those playing along at home to, uh, you try it on your own meter and see how low you can get. Now on the lower uh value. Like really low in value inductors Of course I you know you're getting pretty close to a short circuit so you don't expect this to work. and sure enough, it doesn't work that well.

but I won't go through like all the whole ranges and everything. But you can use this like to measure at least reasonably sized value inductors and get a like, at least a usable indication you've just got to have your noggin on when you use your uh confuser here. uh to make sure you don't don't get your moon units mixed up. But yeah, you can, actually, um, get reasonable indications of inductor values.

Who knew? multimeter for measuring inductors? Neat little trick. Doesn't work in all cases, but hey, give it a try at home if you like that video found it useful. Please give it a big thumbs up. And uh, leave your results down in the comments down below to see how your meter fares on what, uh, different uh values and types of inductors and frequency hooking up the scope.

All that sort of jazz? Fascinating, huh? Catch you next time.