Hi gents,
Sorry if this question makes me seem stupid 😃
How do I test these transistors with a dmm?
I have a bunch of them and Hitachi ones .
Sorry if this question makes me seem stupid 😃
How do I test these transistors with a dmm?
I have a bunch of them and Hitachi ones .
Those are Lateral FET's and that makes simple checks more difficult.
The BUZ is an N channel device so a quick check is to put the meter on a Diode Check range and measure from Drain to Source.
The pinouts are on the data sheets. Connect the Red meter lead to the Drain and the black to Source.
It should not read dead short and could read anywhere from from 'open circuit' to a few ohms depending on any charge on the Gate. If you dab a finger repeatedly on the gate you will alter the charge and so the conductivity.
If you tag a resistor such as a 1Meg (use something high value) between Gate and Source the FET should show open (off) between Drain and Source.
P channel devices are the same but reverse the meter leads.
The BUZ is an N channel device so a quick check is to put the meter on a Diode Check range and measure from Drain to Source.
The pinouts are on the data sheets. Connect the Red meter lead to the Drain and the black to Source.
It should not read dead short and could read anywhere from from 'open circuit' to a few ohms depending on any charge on the Gate. If you dab a finger repeatedly on the gate you will alter the charge and so the conductivity.
If you tag a resistor such as a 1Meg (use something high value) between Gate and Source the FET should show open (off) between Drain and Source.
P channel devices are the same but reverse the meter leads.
You have a tiny diode symbol, surrounded by a yellow line, bottom-right on your selector switch, between 200 ohm and Hfe labels.
* solder crocodile clips to 1M resistor ends (personally I´d use a 100k resistor) so you can clip one end to Gate and the other to Source without soldering.
* if you are just testing to separate usable from dead, that´s enough; if you plan on building something I suggest you find some "How to use a Multimeter" video or online course, you´ll need it for future use.
I´d add:
* solder crocodile clips to 1M resistor ends (personally I´d use a 100k resistor) so you can clip one end to Gate and the other to Source without soldering.
* if you are just testing to separate usable from dead, that´s enough; if you plan on building something I suggest you find some "How to use a Multimeter" video or online course, you´ll need it for future use.
So 360 on the diode range for most meters would mean a volt drop of 0.36 volts is occuring between the probes. That shows there is no short.
If the reading is changing and you have the gate pin floating, then that will be why. The gate is just picking up stray charge. Touch the gate and the reading should change instantly to something else.
If the reading is changing and you have the gate pin floating, then that will be why. The gate is just picking up stray charge. Touch the gate and the reading should change instantly to something else.
You're welcome 🙂
(fwiw, the vast majority of power transistor failures, and that includes all types, is that fail short circuit from Drain to Source or Collector to Emitter)
(fwiw, the vast majority of power transistor failures, and that includes all types, is that fail short circuit from Drain to Source or Collector to Emitter)
Lol, I can imagine. You keep doing the work, we'll keep reading what you're up to 😀
Try to test using the Gate-Source resistor (100k preferred) for a batter stable reading.
Randomly drifting values rub me the wrong way.
Randomly drifting values rub me the wrong way.
Less than 1 minute each. 🙂
Remember I suggested alligator clips, so no soldering.
"300 something mV" for me is a grey area, I typically expect:
* open/infinite
* short or, say, 30-40mV which in practice amounts to same
* 650-700 mV which is normalsilicon junction drop
As you see, 300-350mV is a weird value; to boot it drifts, so, not much use.
And precisely that is what you measured multiple times.
But hey, it´s your time, your transistors 🙂
Remember I suggested alligator clips, so no soldering.
"300 something mV" for me is a grey area, I typically expect:
* open/infinite
* short or, say, 30-40mV which in practice amounts to same
* 650-700 mV which is normalsilicon junction drop
As you see, 300-350mV is a weird value; to boot it drifts, so, not much use.
And precisely that is what you measured multiple times.
But hey, it´s your time, your transistors 🙂
I got myself a Peak transistor tester which is what I used to test them this time around.