Ultimate Electronic Components Testing Guide for Beginners

Ajouté : 2026-05-10

[00:00:00]I'm going to teach you how to test all electron components one by one. You're going also to learn how to test components that needs power like IC's and voltage regulators. I'm going to power the motherboards and check live voltage, check inputs, outputs and much more. I'm going also to teach you the name, symbol, function and purpose of each component. So stay tuned. This is the only video you need to master electronic component testing 100%. Let's get started. How to test diodes. So for diode you have first to locate the cathode and the anode or the negative terminal and the positive terminal and of course set the multimeter to the diode mode as you can see here. So the black probe on cathode red probe on anode we get a drop voltage 0.5 drop voltage. This is good. But if I swap to props like this upload, no reading. This is good diode. What about this one here?

[00:01:17]The big one. This is basically a shortkey diode. And the difference between shortkey diodes and normal diodes are the drop voltage. For normal diode, we find 0.5 0.7 drop voltage. But for the short diode as you can see we going to find very low drop voltage 0.1 0.2. Okay this is shortkey diode or fast switching diode. Let's test this one also. Of course this is a shortkey diode 0.2 0.2 drop voltage. Let's test power MOSFETs. Here we have two power MOSFETs.

[00:02:00]For this kind of MOSFETs always we have gate drain and source. So between source and drain we get a drop voltage 0.4 drop voltage.

[00:02:16]Okay, means this is end channel MOSFET because when you put the red probe on source the black probe on drain and you get a drop voltage in the multimeter means this is in channel okay but if I swap the props same as other moets and transistor no reading open load let's check this one also and find out if it is N channel or P channel MOSFET here s and drain we get a drop voltage 0.5 drop voltage okay means this one also is internal if we swap of course the props nothing in the multimeter those MOSFETs are good what about this components do you see here we have two diodes here connected in their cathodes this is basically a shortkey rectifier And please attention the multimeter is on the diode mode. Okay, we use the diode mode. So this is easy. As I told you, we put the black ro here in the middle. We check the first diode. As you can see, 0.2 drop voltage. Okay. The second diode, we have 0.2 draw voltage. Same drop voltage. And as you can see this is a lower voltage because this is a shortkey diode. What about the bridge rectifier?

[00:03:48]So for the bridge rectifier like this one here we have four terminals and four diodes. The first diode we put the black probe here into positive terminal like this. This is the first diode. We get 0.5 drop voltage.

[00:04:05]Second diode 0.5 drop voltage. Then we have to put the red prop here into negative terminal here and check the third diode 0.5.

[00:04:18]Fourth diode 0.5 means the bridge rectifier is good. Let's check another bridge rectifier. This one for example here here we have second bridge rectifier. As I told you always we locate the terminals. Here we have positive terminal. We put the black probe here and check first diode 0.5.

[00:04:38]Second diode. Okay. And third diode here, four diode. Good bridge rectifier.

[00:04:46]Another very fast test for bridge rectifier. You can just check between positive terminal and negative terminal.

[00:04:54]If you get a double drop voltage, as you can see, means the bridge is good. Let's check this one also here. Do you see between positive terminal negative terminal double drop voltage double drop voltage good rectifier but this is about 80%.

[00:05:12]But the correct test is to check all diodes as you can see like this.

[00:05:19]What about resistors? So resistors as as you know we can base just on colors.

[00:05:25]Here we have brown one, black zero and orange three means this is a 10k resistor. So let's move on to the resistor mode. Okay, we are now in the resistor mode. As you can see here, this is auto range. So let's check this is about 10k.

[00:05:47]As you can see in the multimeter, we have 9.8.

[00:05:51]Okay, so this is good resistor. What about this one here? We have three three and we have two for red means this is a 3.3 kiloohm. Okay, let's check 3.3 as you can see 3.2.

[00:06:08]This is good. So this is good resistor.

[00:06:11]What about this B capacitor? This is basically the CBB capacitor. We find it in motors. Very important capacitor here. For this kind of capacitor, you can just refer to its capacitors. We have here 1 microfarad. 1.5 microfarad.

[00:06:29]So let's move to microfarad. Okay, we have here nanofarad. We have to find 1.5 microfarad. Let's check. As you can see 1.5 microfarad. Okay, this is good. But for this kind of capacitors, you can just test it using the continuity mode like this. Here I have the continuity mode. So let's check it. So no continuity in the multimeter. No continuity. Okay, this is basically a fast testing. If you want to avoid wasting time, you can just check the continuity. But the best way is to check the capacitors. Okay, let's check this capacitor also. Here we have 50 microfarad. Okay, this is an electrolotic capacitor with 50 microfarad. So let's check it. Okay, let's go to microfarad. We have nanop farad here but this is auto range and let's check I have to find 15 microfarad as you can see 13.5 this is good okay always we have to what about this protection capacitors as you can see here we find it in the input here we have 47 microfarad means 0.47 47 microfarad.

[00:07:46]Let's check it. Do you see we have 44 nanofarad which means 0.4 microfarad. So this is good capacitors and as I told you you can just use the continuity mode for beginners and check if there is no continuity like this means the capacitor is good. So we have other kind of capacitor like this here. We find this kind of capacitors in the laptop and computer motherboard as you can see here. So we have basically 25 volt 100 microfarad. Let's check. So we have to find 100 microfarad in this capacitor.

[00:08:28]As you can see we have 9796.

[00:08:31]Okay. So this is good. What about transistors? So for transistors very easy. Let's first select the diode mode here. Okay, the diode mode is selected.

[00:08:45]So for transistor, so let's begin with the first transistor. This one. Let's check these two terminals.

[00:08:54]We have 0.7. This is the first drop voltage. First diode. Let's check here.

[00:09:00]Okay. So I should move on here and put the black rub here. So we have the first diode. Let's go and check this terminal.

[00:09:11]Second diode. Okay. Two diode. So here we have the base base.

[00:09:19]Okay. 710.

[00:09:21]Here 76. So base emitter collector always base emitter is greater than base collector. Let's check this one here also. So these two terminals no drop voltage no drop voltage. Okay. So let me put the red probe here this time. Check here. Okay. The first drop voltage 0.6 or 0.7. Let's check this side.

[00:09:53]Second draw voltage. Okay. Here we have first diode and over here we have second diode.

[00:10:02]Okay. So 60 692 and here 691.

[00:10:10]Let's see here we have emitter collector. What about zener diodes? Do same work principle. Locate first to cathode and anode and always the multimeter to the diode mode. And if we check of course we going to find a drop voltage.

[00:10:32]As you can see, 0.6 drop voltage. If I swap to props, of course, no reading.

[00:10:39]This is good. Let's check this one here also. Okay, as you can see, 0.6 drop voltage. Ceramic capacitors. So to test this kind of ceramic capacitors do multimeter to farad modes. We have farad mode. Let's begin with this one. Here we have 103 means this is a 10 karat equal to 10 nanoparad. So let's check it.

[00:11:10]As you can see we have 9 nanofarad.

[00:11:14]Same for this one we have 103 which equal to 10 nanofarad as you can see here in the multimeter. So this is good.

[00:11:23]What about this one here? So 4 7 and two zeros means this is a 4,700 poparad equal to 4.7 nanofarad. So let's check as you can see in the multimeter 4.1 always we have tolerance. So M means 20% tolerance and for K here this is a 10% tolerance and 1 kilov volt means maximum voltage rating. So those capacitors are good. What about this one here the ceramic or the ACMD ceramic capacitors?

[00:12:06]Let's check it.

[00:12:08]34 35 microfarad. Okay. So this one also is good but we don't have the value above it. So for this kind of capacitors always you have to refer to the data sheet or the schematic or the donor board. What about testing transformers?

[00:12:30]So for transformers we have to select the continuity mode on the multimeter.

[00:12:37]So the continuity mode is selected and check all coils belong to the transformer in primary and secondary. So let's check.

[00:12:51]Okay, this one. This one here. Okay, this is the first coil. Okay, first coil. So second coil. So this side is good. Let's check the other side.

[00:13:06]Okay, this coil is good. Other coil is good. So the transformer is serviceable.

[00:13:12]Time to test anti-c resistor or anticester.

[00:13:18]Very important protection resistor. It's a resistor whose value decreases when temperature increases. So of course let's select mode as you can see. So basically now if we test it we going to find a very low resistor as you can see 2.6 we have 2.6 six in motherboard. This is it over here. As you can see, this is the anti term. Let's check it on the board.

[00:13:48]Basically, this two pins here. So, let's check. As you can see, 6.9.

[00:13:55]So, the behavior of this resistor is that the resistance goes down when temperature goes up. We can even check just using my finger. Look, we have 2.5.

[00:14:08]If I put my finger here, do you see decrease? So the resistance decrease. So the value changes smoothly with do temperature. And remember the NTC gives its real value at 25 Celsius.

[00:14:30]What about testing optoouplers or opto isolators? So very easy for optooupler.

[00:14:38]If you pay attention for the optooupler here we have pin number one. Do you see this dot means this is the pin number one 2 3 4. Here we have the diode and here of course this two here for photo transistor. So basically the a good optooupler is the one that gives here about 1,000 drop voltage between pin number one and pin number two. Let's check. So let's move the multimeter to diode mode. Okay, the diode mode is selected. Let's check between pin one and pin two. Okay, up loop. Let's swap the props. So let's check as you can see 1,000 drop voltage. Okay, let's check this one also. So here we have pin number one as you can see. So let's check between pin one and pin two we have 1,00. Okay, let's check like this.

[00:15:37]1,000. Do you see 1,000? Means this is a good optooupler. For other pins here, you will find up loop in both sides.

[00:15:48]Here we have up loop.

[00:15:52]Also, if we swap the probes, as you can see, we have also uploops.

[00:15:59]>> What about testing fuses? We get the continuity means the fuse is good. Let's check the signal. No continuity. No beep means failed fuse. For this one here, it's clear it is burnt. So we will get no beep, no continuity. The most important is to understand how to change a failed fuse with another serviceable one with same characteristics. As you can see here, we have two amps for this one. 250 volt means you have to change this failed fuse with another one with same characteristics. Now let's test coils or inductors.

[00:16:46]And of course to test coils we will use the continuity mode as you can see here in the multimeter.

[00:16:53]Okay. Good one.

[00:16:56]Good coil.

[00:16:57]This one also is good.

[00:16:59]For this B coil, as you can see, we find it in power supplies and it contains two coils. First coil, red color and second coil. Each coil has two terminals. These two terminals for first coil and these two others for the second coil. So, let's test the first one. We're going to put one probe in the first terminal, the second probe in the second terminal. We have to get a low reading, a beep in the multimeter. As you can see, good coil.

[00:17:35]Let's right now test the second one, one probe in the first terminal, second probe in the second term.

[00:17:42]>> Okay, this is good. This is >> we get a beep means the coil is good.

[00:17:47]The board is powered and I'll teach you how to test IC's step by step. So first you have to locate the inputs and outputs. This is basically the charge ICSL 6251.

[00:18:07]But you got to understand how to test all kinds of IC. So first we have to check the DCN. The first input is the DCN. So the DCN for this kind of IC based on the schematic as you can see is the pin number 24. So here we have the first pin pin number 12 13 24. We have to find 19 volt.

[00:18:40]As you can see in the multimeter we have 18.7. The DCN is present the first input. The second input is the VDD IC power supply. So for this IC we find the VDD in the pin number one. We have to find 5 volt. This is the second input.

[00:19:04]We have 5 volt. The third input very important is enable. We have to find it in pin number three. So let's check. We have to find 3.3 volt.

[00:19:19]So here we have pin number three connected to this resistor. So let's check this resistor.

[00:19:26]We have zero. The 3.3 volt is absent.

[00:19:30]Why? Because the battery is not connected. Once the battery is connected, the enable will be present here. The next input is the V reference.

[00:19:44]Based on the schematic, we have to find it in pin number eight. It's about three V. So let's check. So we have pin 1 2 3 4 5 6 7 8. This is pin number eight. So if we check pin number eight as you can see we have about 2.4 the next input. So please attention to get the outputs we have to check the inputs if the input is not present we will not get the output. So the next input is the VDDP or gate driver supply. We will find it in pin number 15. So the black probe on the ground we have here 12 13 14 15. We have to find 5 volt.

[00:20:43]As you can see in the multimeter we get 5 volt. And another very important input without it all IC cannot work to boot signal or voltage. Here we will find it in pin number 16. So usually or even always the boot is about 5%. So let's check. So we have 13 14 15 we have 16 here. Let's check.

[00:21:14]We have 4.9. This is 54. So this is basically the most important input. Once we get all these inputs means this switch will be activated. Let's check.

[00:21:28]So here basically we have s and here we have drain and this is the gate. Here we have 19 volt.

[00:21:36]We should find the control signal. Let's check.

[00:21:41]We have 8 volt. Good. Means we will get 19 volt in this side. We get 19 volt. So without all inputs here this IC will not send the control signal to lead 19 volt to pass from this side to this side as you can see. So without all inputs we will not get here 8 volt means the 19 volt will stop here. It will not pass to this side.

[00:22:16]So this is how we test the IC's.

[00:22:20]Basically the IC you cannot test it using just the multimeter. You have to power it and test it. And of course you have always to refer to it schematic or to use its reference and search in the internet to find its pin. So I have a question here. how we can test IC's without powering on the board. So to test IC's without powering on the board, I'll give you basically two or three methods. The first method is to select the continuity option on the multimeter. We have here continuity option and to check the ceramic capacitors around the IC.

[00:23:13]If all ceramic capacitors are good, no short means the IC is good not shorted.

[00:23:21]This is the first test. The second test is to power the board and check the heat of the IC. If the heat of the IC is not normal, overheated means the IC is shorted. The third method is to check the state of the IC.

[00:23:43]Is it good or not? Using of course the visual inspection. For example, this IC, this is a good IC. This one here blowed IC. This is bad. So without even power the board, the IC is clear. you have to replace it. I hope you understand. So, please don't hesitate to ask.