This is a 1-channel solid state relay (SSR) for AC power that can be controlled directly via a microcontroller.

This device has a 2A resettable fuse to protect against overload conditions. Microcontroller inputs are isolated with an input transistor and opto-isolation that activates the switch on a LOW input signal with almost 0 current from your micro controller!

SSRs are great because they do not have inductive switching noise from a mechanical switch and do not wear out.

The important thing to remember is that due to the design of this switch, DC power is not recommended because it may not switch off without crossing 0 volts.


1 Channel OMRON G3MB-202P Solid State Relay (SSR) Module


  • Led indicator for each relay
  • Usage: General Purpose

Technical Specifications

Input control signal voltage:

  • 0V – 0.5V Low stage (SSR is OFF),
  • 0.5V – 2.5V (unknown state).
  • 2.5V – 20V High state (SSR is ON).
  • SSR Output (each channel):

Load voltage range: 75 to 264V AC (50/60Hz).
Load current: 0.1A to 2A

Power supply: 5VDC 20mA

PCB thickness: 1.6mm.

Size: 34 mm x 25 mm x 25 mm (L x W x H)

SSR Specifications:

  • Manufacturer: OMRON
  • Part number: G3MB-202P, 5V version.
  • Isolation: Phototriac.
  • Zero cross: Yes.
  • Rated output load: 2A at 100 to 240V AC.(50/60Hz).


Input section

  1. DC +: positive power supply (relay voltage power supply)
  2. DC-: connect power negative
  3. CH1: 1 signal to trigger the end of the relay module (low level trigger valid)

Output Section

  1. A1: Relay Normally Open point A
  2. B1: Relay Common