Table of Contents
Why transistor is used in power supply?
The two main roles of transistors are amplifying small signals and switching. In PSUs, mostly NPN FETs are used in the APFC converter and as main switchers. In order to further increase efficiency, they are also used in the secondary side to rectify the DC outputs (synchronous design).
Does a transistor need external power?
Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Compared with the vacuum tube, transistors are generally smaller and require less power to operate.
Do transistors consume power?
Power dissipation At any given time, the power dissipated by a transistor is equal to the product of collector current and collector-emitter voltage. Just like resistors, transistors are rated for how many watts each can safely dissipate without sustaining damage.
What are the two main transistors?
Transistors typically fall into two main types depending on their construction. These two types are bipolar junction transistors (BJT) and Field Effect Transistors (FET).
How transistors work 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. Thus a small input voltage results in a large output voltage, which shows that the transistor works as an amplifier.
What is the power of transistor?
The power dissipated in the transistor is the voltage drop across the collector emitter junction times the collector current (neglecting the base current times the 0.75V base emitter drop). In the linear range this could be something like 6V@100mA = 600mW (a lot for a little transistor).
How many amps can a transistor handle?
Some transistors may only be rated for a maximum of 10-100mA of current to flow through them. If you supply a current over the maximum rating, the transistor might blow up.