Contents
How do you bias a NPN transistor?
Transistor biasing can be achieved either by using a single feed back resistor or by using a simple voltage divider network to provide the required biasing voltage. The following are five examples of transistor Base bias configurations from a single supply ( Vcc ).
What causes a transistor 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 is difference between PNP and NPN transistor?
An NPN transistor has a piece of P-type silicon (the base) sandwiched between two pieces of N-type (the collector and emitter). In a PNP transistor, the type of the layers are reversed. NPN and PNP transistors have very similar schematic symbols. The only difference is the direction of the arrow on the emitter.
What kills a transistor?
Another way to kill a transistor is localized failure modes like second breakdown, thermal runaway, or avalanche, etc. In this case the transistor is dead, a tiny portion of the die inside will have blown and melted, shorting things out, sometimes without any external sign of any problem.
What can damage transistors?
Sometimes external causes may damage or even destroy transistors. Bad handling of FETs can lead to damage by electrostatic discharge. Sometimes this will result in a transistor (or a circuit board) not working when fitted within a system.
What is the purpose of a NPN transistor?
Another common application for NPN transistors is to use them as an amplifier, in which a small increase in the input voltage induces a large change in the output voltage. NPN transistors are used for this purpose in almost all phones electronic devices in which sound amplification or reproduction is required.
Why do we use NPN transistor?
NPN transistors are used when you want to sink a current; i.e. current flows into the collector. PNP transistors are used when you want to source a current; i.e current flows out of the collector. As a result of this, NPN transistors usually have their emitter connected to the low side of the supply.
How do NPN and PNP transistors operate?
The operation of the PNP and NPN transistors mainly utilizes holes and electrons. These transistors can be used as amplifiers, switches and oscillators. In PNP transistor, the majority charge carriers are holes, where in NPN the majority charge carriers are electrons.
What are the working principles of transistor?
Working Principle of Transistors. When no voltage is applied across the transistor, diffusion of free electrons across the junctions produces two depletion layers . For each depletion layer, the barrier potential is about 0.7 V at 25°C for a silicon transistor and 0.3 V for a germanium transistor.