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Do You Know About the Solid State Switch?

As early as the 1800s, relays were used as amplifiers in long-distance telegraph circuits. They repeated the signal of a circuit and retransmitted it on another circuit. They were also used in telephone exchanges and early computers to perform logical operations. Nowadays, relays are widely used to switch starter coils, heating elements, indicator lights, and sound alarms. The basic function of a relay is similar to that of a valve. One controls the flow of liquids, gases, and air, and the other controls the flow of electricity. In electromechanical relays, contacts open and close through magnetic force. Solid state switch does not have contacts, and the switch is electrically completed.

Introduction of solid state switch

Solid state switch can be seen as modern 21st-century versions of electromechanical relays. These relays consist of sensors, electronic switching devices, and coupling mechanisms. Using semiconductors, the relays open and close when a small external voltage is applied to their control terminals. It consists of three circuits: input circuit, control circuit, and output circuit. The function of the input circuit is the same as the coil on an electromechanical relay. When the voltage is higher than the starting voltage, the circuit is activated, and when the voltage is lower than the relay's minimum release voltage, the circuit is closed. The control circuit determines when the output component is powered on or off. Therefore, the solid state switch acts as a coupling mechanism between the input and output circuits. Examples of applications of solid state switch, a kind of programmable RF switch include medical equipment, HVAC systems, professional food equipment, theater lighting, and industrial machinery.

Advantages of solid state switch

The 4 state switch, also known as solid state switch, is a noise-free electrical device that operates quietly without any movable parts.  They do not have a bulky electromagnetic coil, making them a compact alternative. Their small size also saves valuable installation space. However, their small size does not make them less functional than electromechanical relays. In fact, because optocouplers completely isolate relay circuits, there is no need to worry about relays being burned by excessive voltage.

Now, in order to benefit from the almost infinite service life of the solid state switch, they need to be properly maintained and used. One of the problems that can occur when using the solid state switch is a large amount of residual resistance. This resistance generates heat, which can be eliminated by using heat sinks. Without heat sinks, the service life of the solid state switch will be greatly shortened. So consider purchasing the heat sink and the solid state switch together.

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