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How do you test a transistor for a switch?
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).
How can a transistor be used as an amplifier or a switch?
The transistor will operate as an amplifier or other linear circuit if the transistor is biased into the linear region. The transistor can be used as a switch if biased in the saturation and cut-off regions. This allows current to flow (or not) in other parts of a circuit.
Why transistor is used as an amplifier?
A transistor acts as an amplifier by raising the strength of a weak signal. The DC bias voltage applied to the emitter base junction, makes it remain in forward biased condition. The low resistance in input circuit, lets any small change in input signal to result in an appreciable change in the output.
How do you test the resistance of a transistor?
To test your transistor, first clamp the black probe of a multimeter to the transistor’s base. Then, touch the red probe to the emitter and read the display to see if the resistance is high or low. Next, move the red probe to the collector, and check that the reading is the same as it was before.
How to check the hfe of a transistor?
hFE also known as beta is dc gain stands for “Hybrid parameter forward current gain, common emitter” used to measure the hFE of a transistor which can be found by the following formula. hFE = βDC = IC / IB It also can be used to check a transistor and its pin terminal as shown in fig 1.
What happens when you use a transistor as a switch?
Transistors that are fully “ON” are said to be in their Saturation region. Transistors that are fully “OFF” are said to be in their Cut-off region. When using the transistor as a switch, a small Base current controls a much larger Collector load current.
Can a multimeter be used to check a transistor?
It also can be used to check a transistor and its pin terminal as shown in fig 1. To check a transistor in hFE mode, there are 8 pins slot in the multimeter indicated by PNP and NPN as well as E C B (Emitter, Collector and Base).