What are SSR used for?
A solid state relay (SSR) is an electronic component that switches power (current) to a load circuit and provides electrical isolation between an application’s control circuit and load circuit. It is a competitive technology to electromechanical relays and other switching technologies.
Do solid state relays need a fuse?
USING A FUSE : to protect the solid state relays against load short circuits, fuses must be used, particularly fast-acting fuses for small ratings. The I²t value of the fuse must be less than half of the I²t value of the relay.
How does a solid state relay ( SSR ) circuit work?
The red line associated with pin3 of IC 741 can be toggled through an opto coupler for the required switching from an external source. How it Works: As we can see, the inverting input of the op amp is tied with the 15V zener, which forms a reference level for the op amp pin2.
What should I do when my SSR is turned off?
The SSR may be damaged by counterelectromotive force from the motor. Be sure to install overcurrent protection for when the SSR is turned OFF. 4.Transformer Load When the SSR is switched ON, an energizing current of 10 to 20 times the rated current flows through the SSR for 10 to 500 ms.
Can a MOSFET be used in a SSR circuit?
In one of my earlier posts I explained how a MOSFET based bidirectional switch could be used for operating any desired electrical load, just like a standard mechanical switch , but with exceptional advantages. The same MOSFET bidirectional switch concept could be applied for making an ideal SSR device.
What does DC supply do in SSR circuit?
An input DC supply can also be seen attached across the common gate/source terminals of the two MOSFETs. This supply is used for triggering the MOSFETs ON or for enabling permanent switch ON for the MOSFETs while the SSR unit is operational.