What is DPDT Switch? Double Pole Double Throw Switch

A DPDT Switch or Double Pole Double Throw Switch is a type of switch that has two inputs and four outputs. It is the combination of two SPDT switches. Here, each input has two corresponding outputs. But both inputs are isolated from each other. Similarly, both output pairs are also isolated from each other. DPDT switch can work with four circuits by four different contact positions. It works with two modes of routing operation. So the function of the DPDT switch is not only limited to switching or on/off functions. Even, it has a routing function also.

The working principle of the DPDT Switch is very simple. For example, we named the two inputs as input 1 and input 2. The corresponding output of the input 1 is output 1.1 and output 1.2. Similarly, the corresponding output of the input 2 is output 2.1 and output 2.2.

So when the switch is in one position, the input 1 will be connected to the output 1.1 and disconnected from the output 1.2. At the same time simultaneously, the input 2 will be connected to the output 2.1 and disconnected from the output 2.2.

When the switch is in another position, the input 1 will be connected to the output 1.2 and disconnected from the output 1.1. At the same time simultaneously, the input 2 will be connected to the output 2.2 and disconnected from the output 2.1.

Here, you can see the symbol of DPDT Switch.

Let's see the circuit diagram of DPDT switch to understand its working principle

Here in the above wiring diagram of DPDT Switch, you can see, we have taken four LEDs and two batteries. The LED 1 and LED 2 are connected to the battery 1. The LED 3 and LED 4 are connected to the battery 2.

So, at one position of the switch, the LED 1 and LED 3 will glow together while LED 2 and LED 4 will be in off condition. When the switch is in another position, the LED 1 and LED 3 will be turned off while LED 2 and LED 4 will be turned on.

The DPDT switches are used in complex electronic circuits, electrical pilot circuits, control devices, etc.

Some Common Applications of DPDT Switches are,

1. DPDT switches can be used to control the direction of DC motors. By switching the polarity of the motor's power supply, the motor can be made to rotate in either direction.
2. DPDT switches can be used to switch the polarity of a circuit. This is useful in applications such as reversing the direction of current flow and switching the polarity of signals.
3. DPDT switches can serve as selector switches in various applications, such as selecting different inputs or outputs in audio systems, switching between different power sources, or choosing different operating modes.

Read Also: 

• What is SPST Switch? Single Pole Single Throw
• What is SPDT Switch? Single Pole Double Throw
• What is DPST Switch? Double Pole Single Throw
• [Proper] Two Way Switch Connection Diagram and Wiring
• 4 Way Switch Wiring Diagram and Connection

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