Just a quick question.....

Can this be tested in circuit or does it have to be removed from the PC board to properly test it?

Thanks

 

How are you planning to test it?

The only thing you can test for is to look for shorts between the leads, gate, source and drain. Any resistance test will be influenced by the circuit to which it is attached.

Removing the component is the only way to properly test it.

 

How are you planning to test it?

The only thing you can test for is to look for shorts between the leads, gate, source and drain. Any resistance test will be influenced by the circuit to which it is attached.

Remove the component is the only way to properly test it.

Thanks.
I've been on YouTube for about an hour looking for a video that shows how to test these an amazingly, I couldn't really find one on the Schottky rectifier. At least not one in English.

 

OK,
I removed the MOSFET from the board and tested it....

1). Finger across all 3 terminals to drain any charge
2). Meter set to DIODE TEST Function
3). Negative lead placed on SOURCE terminal
4). Positive lead placed on DRAIN Terminal
----- Result = Open, no continuity ------
5). Moved Positive lead to Gate and held there for 30 seconds
6). Move Positive lead back to DRAIN terminal
------ Result = 485 displayed on the meter

Did I test it properly?
Does this prove the MOSFET is working properly?

 

OK,
I removed the MOSFET from the board and tested it....

1). Finger across all 3 terminals to drain any charge
2). Meter set to DIODE TEST Function
3). Negative lead placed on SOURCE terminal
4). Positive lead placed on DRAIN Terminal
----- Result = Open, no continuity ------
5). Moved Positive lead to Gate and held there for 30 seconds
6). Move Positive lead back to DRAIN terminal
------ Result = 485 displayed on the meter

Did I test it properly?
Does this prove the MOSFET is working properly?

I don't think so.
I would test it in a test circuit, i.e. a load resistor on the drain and a square wave signal on the gate (with protective series resistor).
If you don't have proper test equipment you can use fixed gate voltages and see if the D-S channel turns on and off.

 

Removing the component is the only way to properly test it.

I don't think so. I would test it in a test circuit,

Here's where I got the above info.......

 

Tested it today using this method.......PASSED

 

If you have one of those ESR-Capacitance-Inductance testers from amazon or ebay, that'll work. I had a bad MOSFET one time, prob from static discharge, and the meter was able to verify the type of mosfet it was, but after it was acting like it's not suppose to, I tested it again and the meter showed it as diodes in series. Or like previous guy said, build a simple test switch circuit and verify

 

Two of the most useful instruments for testing components that I have!.... 9 times out of ten will test in circuit.

 

View attachment 132785
Two of the most useful instruments for testing components that I have!.... 9 times out of ten will test in circuit.

ok. If others can verify their usefulness I'll get them both. Electronics has become a hobby for me. Those might make it more fun

 

ok. If others can verify their usefulness I'll get them both. Electronics has become a hobby for me. Those might make it more fun

Have a look at Peak Electronics web site,
www.peakelec.co.uk/
I only wish I had these 30 years ago!!! My ex business partner who bought me out when I retired, has 15 staff repairing everything and anything electronic and has about a dozen of each of these along with their Zener testers.
The reason I bought the dca 75 as opposed to the cheaper dca 55, is because it can connect to a pc and show multiple curve traces in real time. The advantage of this in design work is fairly obvious, but when servicing, sometimes an unidentified device is encountered. with dca 75, you can hook it up and presto! it is identified for you!
Another thing that often crops up is, you find a device that appears short or open circuit, you try to look up the part number with no luck. If you look around in whatever the equipment is, chances are there is another one somewhere that seems to measure ok with an ordinary test meter but what is it? Jfet,, n or p channel, mosfet, bipolar, triac, etc. Well, with the dca 55 or 75, connect it up usually in circuit, and in moments you will know what KIND of device it is which enables you to find something similar as a replacement.

Now I am a hoarder, yes I admit it! and I have literally TONS of stuff which I might need oneday lol, but this huge amount of what my other half calls junk, saves me a fortune by recycling parts for repairs and projects. the inductor/capacitor checker is very useful for measuring unknown inductors (along with a saturation curve tracer I designed.)
Another useful feature is being able to match capacitor values, It is not uncommon for ceramic, polyester, and many other types to be way off marked value even when brand new!

 

Which device is best for testing Zener diodes and MOSFETS ?

 

Which device is best for testing Zener diodes and MOSFETS ?

The best one for testing mosfets is the dca 75 because of the ability to connect it to a computer to see operating curves etc, If you only need to know a few specs then the dca 55 is very good. both will test transistors, diodes.......Voltage regs and zeners up to about 9 Volts.
For Zener testing the Zen 50 will test them to 50 Volts. All their products are of excellent quality, and several years of everyday use has proved their reliability.
The one thing to beware of when using the inductor tester is NOT to have it too near an inverter fluorescent bench light as the inductor will pick up radiation and upset the measurements. Usually 1 ft (30cm) is sufficient distance.