6 Solid Reasons to Use Solid State Relays

6 Solid Reasons to Use Solid State Relays

Relays are electrically powered switch devices used to control and manage high-power equipment that operates using low-signal signals.

Relays are electrically powered switch devices used to control and manage high-power equipment that operates using low-signal signals. Relays manage a single circuit by shifting contacts in a control circuit and not changing the load straightforwardly. A relay can be seen as a power shifting apparatus used to simplify power management without manual operations. A relay only uses a small electrical signal to switch the power. This signal can be understood as a “gatekeeper” as an analogy for a larger electrical signal. Its ability to have low-power control over a high-power signal is the prime reason behind relays enjoying wide popularity in electronics.

Solid State Relays

Solid State Relays utilize low power electrical signals to operate an optical semiconductor signal, most commonly with an optocoupler’s help that communicates the output signal. During use, the input optical signal plays the role of a “switch” that allows a high voltage signal to travel through the SSR’s output element. There are multiple ways of doing this, but the general factor between them all is the lack of moving parts, making it a solid-state. Unlike conventional contactor relay, solid state relays have no moving parts and as a result, have a very long life.

Advantages of Solid State Relays

Due to the absence of moving parts in SSR, it offers various advantages compared to Electromechanical Relays (EMRs). These advantages range from a simple design, lengthy life, reduced power intake, swift switching, soundless operation, and many others.

Simple Design

The circuit board layout and the total space of SSR are lesser than EMRs having the same features. SSRs are also lighter than EMRs by a whopping 70 per cent. Due to the size and weight benefits, SSRs help systems where there is less installation space. The operation of SSR is independent of its position. This means that it can be placed both vertically or horizontally. Even though SSRs are smaller in size, they are equally powerful as EMRs.


We know that SSRs do not have any movable parts. This helps in avoiding issues like mechanical wear and tear or arcing. Hence, they are suitable for devices that remain in constant operations.

Reduced Power Consumption

Unlike EMRs, SSRs do not require to charge bulky coils or open and close contacts. SSRs only require an inflowing power that is enough to operate an optical coupler LED, which does not consume high power. While EMRs operate with hundreds of milliwatts to a few watts, SSRs only need a few microwatts to some milliwatts to function.

Swift Switching

SSRs offer speedier switching than EMRs. This is because there are no physical parts to move to switch on or off. The switching duration only depends on the LED turning on or off, which reacts to a control signal almost immediately.

Silent Operation

SSRs use electronic circuits to offer switching operations. Their switching operation is entirely a silent one since there is no moving physical component. This feature is of immense advantage in medical and commercial applications.

Less EMI Sound

The low noise in SSRs offer a zero-voltage switching on and a zero-current switching off. This reduced the electromagnetic interference (EMI) to the minimum. The zero-crossover switching characteristic is one of the most crucial advantages of SSRs. It provides highly reduced electrical disturbances.

Schneider Electric India offers professional-grade solid-state relays widely preferred for a range of appliances for residential and commercial requirements. They are affordable and long-lasting.