EASY TESTING OF TRANSISTOR

Easy testing of transistor with {dmm }

Dmm  is the most use testing equipment  which can be use to diagnose many electronics components resisthors and others by field technician and even engineers.using dmm to test a suspected faulty NPN or PNP bipoloar transistor is very simple task

On this article I will show you how to test a transistor using a DMM{BEGINNER}

Note: This test only verifies that the transistor is not shorted or open, it does not guarantee that the transistor is operating within its designed parameters.

 It should only be used to help decide if it needs “replacement” or “move  to the next component”.

 This test works only on bipolar transistors .

       Transistor testing steps

Step 1 set your dmm to diode mode

Step2 remove the transistor from the circuit board for the best result.

Step 3: (Base to Emitter)

Hook the positive lead from the multimeter to the to the BASE (B) of the transistor. Hook the negative meter lead to the EMITTER (E) of the transistor. For an good NPN transistor, the meter should show a voltage drop between 0.45V and 0.9V. If you are testing PNP transistor, you should see “OL” (Over Limit).

Step 4: (Base to Collector)

Keep  the postitive lead on the BASE (B) and place the negative lead to the COLLECTOR (C).

For an good NPN transistor, the meter should show a voltage drop between 0.45V and 0.9V. If you are testing PNP transistor, you should see “OL” (Over Limit).

Step 5: (Emitter to Base)

Hook the positive lead from the multimeter to the to the EMITTER (E) of the transistor. Hook the negative meter lead to the BASE (B) of the transistor.

For an good NPN transistor, you should see “OL” (Over Limit).If you are testing PNP transistor, the meter should show a voltage drop between 0.45V and 0.9V.

Step 6: (Collector to Base)

Hook the positive lead from the multimeter to the to the COLLECTOR (C) of the transistor. Hook the negative meter lead to the BASE (B) of the transistor.

For an good NPN transistor, you should see “OL” (Over Limit).If you are testing PNP transistor, the meter should show a voltage drop between 0.45V and 0.9V.

Step 7: (Collector to Emitter)

Hook the postitive meter lead to the COLLECTOR (C) and the negative meter lead to the EMITTER (E) – A good NPN or PNP transistor will read “OL”/Over Limit on the meter. Swap the leads (Positive to Emitter and Negative to Collector) – Once again, a good NPN or PNP transistor should read “OL”.

If your bipolar transistor measures contrary to these steps, consider it to be bad. You may also be able to use the voltage drop to determine which lead is the emitter on an unmarked transistor, as the emitter-base junction typically has a slightly higher voltage drop than the collector-base junction

Leave a Reply

Close Menu