What is a transistor and its symbol?

Transistor:

1. A transistor is a miniature semiconductor that regulates or controls current or voltage flow in addition to amplifying and generating these electrical signals and acting as a switch/gate for them.
2. Typically, transistors consist of three layers, or terminals, of semiconductor material, each of which can carry a current.
3. A transistor is made up of three terminals which are called the emitter, base, and collector.
4. An electrical signal is applied to the base, and the current flow between the emitter and collector.
5. A transistor basically acts as a switch and an amplifier.
6. The standard units of a transistor for electrical measurement are Ampere (A), Volt (V), and Ohm (Ω), respectively.
7. The word transistor is a combination of transfer and resistance.
8. This is because it transfers the resistance from one end of the device to the other end or we can say, transfer of resistance.
9. Hence, the name transistor. Transistors have very high input resistance and very low output resistance.

Types of transistors:

Transistors are broadly divided into these types:

Bipolar transistors (bipolar junction transistors: BJTs). They are further classified into two categories

1. An NPN transistor has a piece of P-type silicon (the base) sandwiched between two pieces of N-type (the collector and emitter).
2. In a PNP transistor, the type of the layers is reversed.

Field-effect transistors (FETs) are further classified into two categories:

1. Insulated-gate bipolar transistors (IGBTs).
2. Metal-oxide-semiconductor field-effect transistor(MOSFET)

Thus, a transistor is a miniature semiconductor that regulates or controls current or voltage flow.