how to know the transistor is npn or pnp
please whith full detail
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I just remember another way. It goes like this.
First you get a Japanese analogue multi-meter (eg Sanwa 360YTR) and
switch to X1K range. The reason for using Japanese meters is because
its Red Probe carries -V while the Black Probe is +ve. The European
meters are the other way round (I never own an US analog meter). So
remember that if you use meters other than those made in Japan. The
result would be opposite ie NPN->PNP & PNP->NPN.
1. Put the R(ed) probe on C and B(lack) probe on E. The meter should
be at infinity.
2. Wet one of you fingers, if it is too dry, with some saliva and touch
the B & C of the transistor that you are testing. Make sure that the
emitter is not touched by your finger.
3. If the meter swings, it's a PNP transistor. The more the meter
swings, the higher the gain of the transistor.
4. If the meter stays still, reverse the 2 probes ie. B probe on C and
R probe on E. Repeat #2 again.
5. If the meter swings now, it's an NPN transistor.
6. Wipe you finger with a tissue paper.
Of course there are a few assumptions made before you test the
transistor. You must know the orientation of C, B & E before you
perform the test. If the meter swings a little before you touch the
Base, the transistor most probably is leaky. But if the C&E is having
a resistance of approximately 50 ohms on both ways, it could be a FET
(D&S).
Regards.
Allen
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| |
| |
| |RED PROBE
|C |
B |/ / \
-----| (_/_)
|> \_/
|E |
| |
| |BLACK PROBE
| |
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