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Which is the turn on time and turn off time of transistor switching times?
Fall time (tf) − The time taken for the collector current to reach from 90% of its maximum value to 10% of its initial value is called as the Fall Time. Turn-off time (TOFF) − The sum of storage time (ts) and fall time (tf) is defined as the Turn-off time.
What is the cause of storage time?
The time required for excess minority carriers stored in a forward-biased pn junction to be removed after the junction is switched to reverse bias, and hence the time interval between the application of reverse bias and the cessation of forward current.
What’s the difference between a transistor and a NPN switch?
The equations for calculating the Base resistance, Collector current and voltages are exactly the same as for the previous NPN transistor switch. The difference this time is that we are switching power with a PNP transistor (sourcing current) instead of switching ground with an NPN transistor (sinking current).
What is the turn on and turn off condition of the NPN?
My intention is to calculate the turn on and off condition of the transistor Q1. R1 and R2 (10 kΩ each) are internal to the transistor. Following is my understanding, whenever there is voltage at the input V1, it will equally divide across R1 and R2.
When does Q1 turn on in the NPN?
When it reaches 0.7 at Vbe, Q1 will be turned on. If I want to increase the turn on voltage of the transistor, introducing voltage divider at the input (before resistor R1) will be sufficient. I want to on and off the transistor above to a fixed voltage, say 5 V. Please advise my understanding.
What do you need to know about bipolar NPN transistors?
One other point to remember about Bipolar NPN Transistors. The collector voltage, ( Vc ) must be greater and positive with respect to the emitter voltage, ( Ve ) to allow current to flow through the transistor between the collector-emitter junctions.