Differences Between Vacuum Relay, SPST-NC, STST-NO, SPDT, and DPDT Switches

The differences between vacuum relay, SPST-NC, SPST-NO, SPDT, and DPDT mainly lie in their structure and function:

1. Vacuum Relay:
   

   • Structure: Operates within a vacuum chamber to prevent arc formation.
   • Function: Suitable for high-voltage switching, reduces contact wear, responds quickly, and is commonly used in high-voltage circuits requiring fast switching.
     
     

2. SPST-NC (Single Pole Single Throw Normally Closed):

   • Structure: Has one input and one output, and the circuit is closed by default.
   • Function: Used to keep the circuit closed when not energized and open the circuit when energized.
     
     

3. SPST-NO (Single Pole Single Throw Normally Open):

   • Structure: Has one input and one output, and the circuit is open by default.
   • Function: Used to keep the circuit open when not energized and close the circuit when energized.
     
     

4. SPDT (Single Pole Double Throw):

   • Structure: Has one input and two outputs.
   • Function: Can switch between two outputs, commonly used in applications requiring switching between two circuits.
     
     

5. DPDT (Double Pole Double Throw):

   • Structure: Has two inputs and two outputs.
   • Function: Can switch two independent circuits simultaneously, suitable for applications requiring simultaneous control of two circuits.
     
     

These types of relays and switches have different uses in circuit design, and the choice depends on specific application requirements.