In our one previous article we discussed about Arduino Relay Modules. Solid-state relays are not really relay rather are electronic components which has some functions like electromechanical relay. Here is an Article on Solid-State Relay (SSR) For Arduino. Solid-State Relay (SSR) provides limited switching arrangements (SPST switching, terminologies like SPST discussed on our article on electrical switches.)
What is Solid-State Relay (SSR)?
For switch on/off effect solid-state relays depends on transistors, thyristors or some similar components – not coil with moving part. Therefore very durable, suitable for high switching frequencies and unfavorable environmental conditions (such as environments with explosive gas mixtures).
With semiconductor relays it is possible to switch AC voltage during the zero crossing, whereby disturbing pulses can be avoided. A galvanic isolation between the control circuit and the load circuit is achieved with semiconductor relays by integrated optocouplers in the component. Semiconductor relays have higher losses in the load current path than mechanical relays and therefore often have to be mounted on a heat sink. In addition, there are semiconductor relays that switch at the peak of the mains voltage or immediately when driving, vertex switches are used to switch inductors that have little or no residual magnetization and thus no hysteresis.
What Are Advantages, Disadvantages of Solid-State Relay (SSR)?
Advantages of Solid-State Relay (SSR) :
- Smaller profile than mechanical relay of same specification
- Silent operation
- Faster than electromechanical relays
- Higher lifetime
- No sparking
- Durable, not sensitive to magnetic fields
- Can operate directly from logic level outputs
- Works for both digital and analouge
Disadvantages of Solid-State Relay (SSR) :
- Higher electrical noise
- Voltage/current characteristic is not linear (electromechanical relay has linear resistace
- Possibility of spurious switching
- Higher transient reverse recovery time
Both, electromagnetic relay and Solid-State Relay (SSR) needed for a beginner to test for controlling DC things. However, using Solid-State Relay (SSR) for AC household supply demands higher experience for making sure that the circuit is fault free. Electromagnetic relays are time tested “switches” suitable for many works and working principle essentially easy.
The back surface is usually made of smooth metal, designed to be bolted with heatsink grease to a heatsink. Heatsink can be just a large enough metal plate rather then a finned one.