What type of electrical Switch' is suitable for your building? -Types of electrical and mechanical switches

The switch is a device designed to interrupt the current flow in a circuit by making or breaking an electrical circuit. The electrical switches are available in manual and automatic operation.

The switch is connected between phase circuits to turn ON and OFF the electrical equipment. So, the switches are part of a control system to operate electrical and electronic devices.

photo by Tim Sullivan On stack snap

We all know that a switch performs two essential functions, with the help of contacts. The contacts make ON or OFF conditions.

What is the ON-Condition of Switch?

In this condition, a switch creates a closed path for the current flow by closing its contact. So, that electrical load consumes electricity from the source.

What is OFF-Condition of Switch

In this condition, a switch creates an open path between load and source. Hence, no electricity will be consumed by the load.

Types of Switches Based on Operation

There are two types of electrical switches based on their operation 1) Mechanical switch; 2) Electrical switch

Mechanical Switch

Mechanical Switch requires physical or manual contact with the device switch for operation.

Electrical Switch

The electrical switch has the ability to operate automatically without any manual contact under the semiconductor's action.

Classification of Mechanical Switches

According to the number of poles and throws

Mechanical switches are further classified into 5 types based on their number of poles and throws.

• Single Pole Single Throw, (SPST) 
• Single Pole Double Throw (SPDT)
• Double Pole Single Throw (DPST)
• Double Pole Double Throw (DPDT)
• Intermediate switch

The connection of the switch is determined based on the number of poles and throw.

What are poles in the switch?

Poles are the number of the closed independent circuit which mean number incoming circuit switch can connect.

What are throws in the switch?

A number of positions, in which the given pole is closed.

Single pole Single Throw Switch (SPST)

SPST is the basic ON or OFF switch that is used to make or break the connection between two terminals. This has the ability to control only one circuit. These are the switches normally used in our homes, malls, etc.

One input and one output 

The one-way electrical switch is the other name for a single-pole single-throw switch.

Application of SPST switch

1. The application of the SPST switch is the light switch. 
2. These types of switches are best suitable for connecting low-voltage circuits. 
3. SPST switch ON lights, fan Television, etc. 

Single pole Double Throw Switch (SPDT)

The single pole double throw (SPDT) switch will have three terminals. One terminal connects the incoming circuit and the remaining two terminals connect the outgoing circuit. Yes, the single switch has the ability to control two device 

One input two output

Application Of SPDT

The three terminals of the switch allow us to control the single electrical equipment from two different places or to control the electrical equipment in different modes.

For example, the stairway switches circuits and Controlling fan speed using SPDT switch.

Double pole Single Throw (DPST)

DPST switch contains 4 terminals, that is two input terminals two output terminals. The single switch has the ability to energize two outgoing circuits. It means, if the Switch is actuated then both circuits will get energize and operate the electrical equipment at the same time. In DPST two identical switches are located side by side.

Two input Two output at different load

The one-way electrical switch is the other name for a single-pole single-throw switch.

Application Of DPST

The DPST switch used in a hair-dryer operates the heater and fan at the same time. One circuit operates a hair-dryer, and another circuit operates a fan.

Double pole Double Throw (DPDT)

DPDT switch similar to SPDT switches but it has totally six terminals. where we connect our power source and output source. The two separate input circuit connects to one set of two outputs. The DPDT switch has three different positions, 

The center position will keep the switch in OFF mode, and actuating the switch position forward or backward will energize the two different circuits.

Application Of DPDT

The DPDT switch used in the hairdryer can control the performance. Actuating the switch forward will energize the circuit with low-performance mode and actuating the switch backward will energize the circuit with high-performance mode.

Intermediate Switch

An Intermediate switch is where three points control the same circuit. This switch can adapt to any condition and can be used for lighting situations, but in reality, it is more expensive.

Types of Switch based on holding the current state

Mechanical switches are also categorized into two on the basis of holding the current state.

• Latch Switch
• Momentary switch

Latch Switch

The latch switch remains in its On/ Off state until the new command initiates this switch. For example, Once a switch of a ceiling fan is commanded to ON state, it allows the ceiling fan to consume power until new command OFF is initiated.

Momentary Switch 

Momentary switches remain in their state until the specific command. For example, the buzzers of the bus make a horn sound only in a state of compression. Releasing the compression on the button will make its state off.

 8 types of the latch and momentary switch

 Latch switch and momentary switch are eight types.

• Push-button Switch
• Limit Switch
• Pressure Switch
• Float switch
• Temperature Switch
• Toggle Switch
• Rotary Switch
• Joystick Switch

Push Button Switch

The Push-button switch has two contacts. Whenever the push button is pressed two contacts will touch each other and the electricity will start to flow in a closed circuit. When the button is released, the circuit will be broken and became an open circuit.

The two contacts of the push-button switch will be in the open position. This is also known as NO switch or Normally Open Switch.

Limit Switch

A Limit switch is an electromechanical device that consists of an actuator. This switch is mechanically linked to a set of contacts.  When the object or something comes into contact with the actuator, the switch operates the contact to make or break an electrical circuit. 

Limit Switches are used for controlling machinery as part of a control system, as a safety interlock, or to count objects passing a point.

Pressure Switch

Pressure switches are designed with a C-shape diaphragm to indicate the pressure. These switches are used to sense the pressure of liquid substances such as oil, air, water, in industries.

The contact of the pressure switch allows the electricity flow only when the pressure of the system is increases or decreases from the set point.

Float Switch

The body of the float switch is made up of polyethylene which helps the float switch to float on the surface of the water.

These switches are float on the liquid and automatically controls the ON/OFF operation of electrical devices. Whenever there is a movement in the switch such as up and down then normally open (NO) contact will become normally close (NC) or normally close contact will become normally open (NO).

The float switch detects the level of liquid and prevents the overflow of water in tanks by automatically switches off the operation of the motor or pumps. This is also used to control alarms.

Temperature Switch

The temperature switch is an On / Off switch that works based on the temperature. This switches widely in industrial purposes to limit or to maintain the temperature of electrical devices. The operation of the switch is based on the value of the measured temperature.

This switch consists of temperature sensing devices like a thermostat or RTD to sense and monitor the equipment and machinery in industries.

Toggle Switch

This type of switch is commonly used in household applications to ON and OFF electrical appliances.

This type of switch has a lever which we can move up or down to ON and OFF application

Rotary Switch

This type of switch is used to connect one incoming circuit to many outgoing circuits. The rotary switches are mostly used in control panels to connect terminals of multimeter, ammeter channel selector.

The other name for the rotary switch is a single-pole multi-throw switch but the arrangement of this switch is different.

Conclusion

I hope you came to know about types of electrical switches. Now, the question is, "what type of switch is used in your home?."

Leave a comment...😀