Difference between the Relay and the FET?

The Relay is a mechanical switch. A tiny arm moves inside the relay providing either an open or closed contact. A FET switch (Field Effect Transistor) is a solid state switch, no moving parts. The FET switch is designed for interfacing to a PLC.

The maximum rating for the FET is 36 VDC @ 100mA. The Relay is designed for interfacing directly to a device such as a light buzzer or another relay. The maximum rating for the Relay is 60 VDC/VAC @ 1A.

Here’s a table highlighting the main differences between a relay and a FET (Field-Effect Transistor):

Relay FET (Field-Effect Transistor)
Electromechanical device that uses an electromagnetic coil to control the switching of contacts. Electronic device that uses voltage applied to a gate terminal to control the flow of current between source and drain terminals.
Contains moving mechanical parts, including an armature and contacts. Solid-state device with no moving parts.
Can handle both AC (Alternating Current) and DC (Direct Current) signals. Primarily used for DC applications but can also handle AC signals with certain specifications.
Typically slower switching speed due to mechanical movement. Generally faster switching speed since it operates electronically.
Has a limited lifespan due to mechanical wear and tear. Has a longer lifespan since it has no mechanical parts to wear out.
Suitable for higher current and voltage applications. Suitable for lower current and voltage applications.
Provides electrical isolation between control and switched circuits. Does not provide electrical isolation and may require additional circuitry for isolation purposes.
Generally larger in size and bulkier. Smaller in size and more compact.
More susceptible to electromagnetic interference (EMI). Less susceptible to electromagnetic interference (EMI).
Higher power consumption due to coil energization. Lower power consumption as it operates based on voltage control.
Audible clicking sound when switching. Silent operation since there are no moving parts.

It’s important to note that this table provides a general comparison between relays and FETs. Different types of relays and FETs may have specific characteristics and applications that deviate from the general characteristics mentioned here.