Question

Which of these PS unipolar transistors?
(a) p – n – p transistor
(b) n – p – n transistor
(c) Field effect transistor
(d) Point contact transistor

Answer 1

Hint: A field effect transistor is a unipolar device since the conduct of the current is due to majority charge carries only. This clearly indicates a Unipolar transistor.

Complete step by step solution:
BJI (BP polar junction transistor) the name bipolar comes from the fact that this type of transistor contains two types of semiconductor material one positive type (P–type) and one negative type (n–type) through which current flow. Bipolar junction transfer contains silicon
In p-type layers Ru a BJT's Jon to alter the electrons that enter the transistor through its input circuit.

The no type layers on the other hand should encourage electrons to flow out of the transistor. The push and pull affect between the layer enables the electric current to be amplified and controlled.

The configuration of the layer in a BJT determines the electrical current flow and ensures that a charge can't return in the same direction as it came. This setup protects the system from overheating or becoming damaged (npn-pnp)

UJT (Unipolar junction Transistor)

All field effect transistors can be called unipolar devices because the charge that carries the current through the device are all of the same type i.e. either holes or electrons but not both. This distinguishes FET from the bipolar devices in which both holes and electrons are responsible for current flow in any one device

So the correct answer is option (c) i.e. field effect transistor.

Note: Don't confuse between BJT and UJT. BJT contains both holes and electrons but UJT contains one electron or holes.