How do we test the transistor for switching condition?
Remove the transistor from the circuit for accurate test results. 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.
How do you test a FET transistor?
1) Hold the MosFet by the case or the tab but don’t touch the metal parts of the test probes with any of the other MosFet’s terminals until needed. 2) First, touch the meter positive lead onto the MosFet’s ‘Gate’. 3) Now move the positive probe to the ‘Drain’. You should get a ‘low’ reading.
How can check transistor terminal using multimeter?
Connect the base terminal of the transistor to the terminal marked positive (usually coloured red) on the multimeter. Connect the terminal marked negative or common (usually coloured black) to the collector and measure the resistance. It should read open circuit (there should be a deflection for a PNP transistor).
What causes transistors to fail?
Failures can be caused by excess temperature, excess current or voltage, ionizing radiation, mechanical shock, stress or impact, and many other causes. In semiconductor devices, problems in the device package may cause failures due to contamination, mechanical stress of the device, or open or short circuits.
What causes output transistors to fail?
As temperature rises in transistors (and virtually any other electronic device), they are less able to withstand stress. Under adverse conditions, they are more likely to fail when hot. All else being constant, lowering the impedance of the load on the amplifier will cause the output current to increase.
Which is the fastest switching device?
Amongst BJT, MOSFET, JEFT and Triode, MOSFET is the fastest switching device because of its quickest response.
Which transistor is best suitable to achieve fast switching in digital circuit?
Explanation: MOSFET is the fastest switching device among the given four options.
Can a tip42 transistor switch 2 amps?
Your circuit looks OK, but it won’t switch 2 Amps. At 2A the TIP42 has typical DC current gain <=50 at 2A, so you need to feed at least 40mA into its Base. In your circuit Q3 cannot deliver this much, because R11 is limiting its Emitter current to about 9mA. You should reduce the value of R11 to 100 Ohms or less.
When do you use a transistor as a switch?
Transistors have a very high resistance when open and very low resistance when closed. Transistors are used to switch low-level DC only. When transistors are used as switches, a diode can be mounted across the transistor to prevent damage from high-voltage spikes (transients).
How to test an NPN transistor for an open Junction?
To test an NPN transistor for an open or shorted junction, the following procedure is applied: Connect a DMM to the emitter and base of the transistor. Measure the resistance. Reverse the DMM leads and measure the resistance. The emitter/base junction is good when the resistance is high in one direction and low in the opposite direction.
How are the junctions of a transistor tested?
A transistor becomes defective from excessive current or temperature. A transistor normally fails due to an open or shorted junction. The two junctions of a transistor may be tested with a digital multimeter (DMM) set to measure resistance.