A switch is an electrical device that is used to interrupt the flow of Electricity. It can be used to turn on and off any appliances such as fans, television, computers, lights, etc. It is also used to break an electronic circuit when the switch is on means the circuit is closed and the current is flowing and when it’s off the circuit is open and there is no flow of current. Broadly switches can be classified into 2 types, mechanical and electrical.
Types of switches
Mechanical Switches:
- Single pole double throw
- Single pole double throw
- Double pole single throw
- Double pole double throw
- Two pole six throws
- Momentary control switches – temperature, toggle, and rotary
Electrical switches:
- Power diode
- Bipolar transistor
- Metal oxide-field effect transistors
Let us discuss each one of the types of switches in detail:
Mechanical switches:
- It depends upon the poles and throws and therefore it is classified into various types.
Single pole double throw:
- It consists of two terminals, one input terminal referred to as pole and one output terminal referred to as throw.
- Therefore it got the name single pole single throw.
- It is used ins a single loop means the circuit requires to control only one close path.
Single pole double throw:
- It consists of three terminals, two output terminals, and one input terminal.
- It is used to supply current to two loops and is known as a selector switch.
Double pole single throw:
- They are used to control two circuits at a time.
- It has four terminals, two input terminals, and two output terminals.
- They have two switches that are connected with a single lever to operate at the same time.
- They are similar to two single-pole single throws.
Double pole double throw:
- They have six terminals, two input terminals referred to as poles and four output terminals referred to as a throw.
- Two terminals for each pole.
- In this one pair of output or throw is connected with two terminals of input or pole.
Two poles six throws:
- It consists of 12 output terminals and six output terminals for each pole and one input terminal.
- It is used for change over in a circuit with the common input terminal.
Momentary control switch:
- They are divided into categories:
Temperature switch:
- Used in various temperature sensing devices like resistance temperature devices.
- It operates according to the value of the measured temperature.
Toggle switch:
It is used in household applications to on-off electrical appliances.
Rotary switch:
- It is used to connect one line with many lines.
- It is similar to a single-pole multi-throw switch but has a different arrangement.
Electrical switches:
Power diode:
- Silicon is used to make when pn junction is reverse biased power diode acts as a switch off and switch on when the pn junction is forward biased
Bipolar transistor:
It is similar to a normal switch.
Metal oxide semiconductor field-effect transistor:
- Unipolar switch device made of three terminals
- Output( drain), common(source), and input( gate).
- It is voltage controlled.
- On and off is determined by controlling input voltage and resistance across the drain and source.
