Solid State Relay Module 5V — 1-Channel SSR, 100–240VAC / 2A, Zero-Cross, Active-Low, Arduino

Solid State Relay Module — 5V, 1-Channel SSR, 100–240VAC / 2A, Zero-Cross Switching

The 1-channel solid state relay (SSR) module switches 100–240VAC at up to 2A from a 5V active-LOW logic signal — no moving parts, no audible click, no contact wear. Built on the Omron G3MB-202P SSR with built-in phototriac coupler isolation and zero-cross switching, this module is the clean, silent alternative to electromechanical relay modules for controlling AC loads up to ~220W. An onboard 2A fuse provides over-current protection on the AC output side.

The module is active-LOW: driving CH1 LOW energizes the SSR (red LED ON, AC output connected). Logic HIGH or no connection de-energizes the SSR. The input draws <1mA — directly drivable from any Arduino, ESP32, or Raspberry Pi GPIO pin.

Key Features

• Zero-cross switching — switches at AC waveform zero point, minimizing electrical noise and inrush current
• Phototriac coupler isolation — built-in opto-isolation between MCU logic and AC load
• Active-LOW control — LOW = SSR ON; HIGH = SSR OFF
• <1mA GPIO drive — safe for all MCU GPIO pins, no driver transistor needed
• 2A onboard fuse — AC-side over-current protection
• Red LED indicator — illuminates when SSR is energized
• Reverse polarity protection — diode on DC power input
• Screw terminal connections — for both DC control and AC load wiring

Technical Specifications

Supply Voltage	4–6V DC (5V typical)
Supply Current	~10mA when SSR energized
Control Logic	Active-LOW (LOW = SSR ON)
Logic HIGH threshold	>3.1V (when Vcc = 5V)
Logic LOW threshold	<1.2V
GPIO Current Required	<1mA
AC Output Voltage Range	75–264VAC (recommended: 100–240VAC)
AC Output Current	0.1–2A
Switching Type	Zero-cross
Switching Speed	Every half-cycle (~8.3ms @ 60Hz)
Onboard Fuse	2A (AC side, soldered)
SSR Component	Omron G3MB-202P

3.3V Compatibility Note

This module is 5V logic optimized. The logic HIGH threshold to turn the SSR OFF is ~3.1V when Vcc = 5V. A 3.3V MCU GPIO may or may not reach this threshold reliably — adding a pull-up resistor on the CH1 line to 3.3V improves reliability. If Vcc is reduced below 5V, the HIGH threshold scales proportionally.

Wiring Guide

DC control screw terminal (3-pin):

• DC+ → 4–6V DC supply (5V typical)
• DC− → GND (shared with MCU ground)
• CH1 → MCU GPIO (LOW = SSR ON)

AC load screw terminal (2-pin, non-polarized):

• One terminal → AC mains hot lead (incoming)
• Other terminal → Load hot lead (outgoing to load)
• AC neutral connects directly to load (not through relay)

AC safety: When switching mains voltage, ensure all AC connections are properly insulated and enclosed. Mount in a suitable electrical enclosure with terminal strips for safe AC wiring.

SSR vs Electromechanical Relay Module

• SSR (this): Silent, no moving parts, unlimited switching life, zero-cross switching reduces EMI — best for frequent switching, noise-sensitive environments, and long-life applications up to 2A AC
• Electromechanical relay module: Audible click, mechanical wear, can switch DC and higher AC currents (10A+) — best for infrequent switching and higher current loads

Typical Applications

• Arduino / ESP32 AC mains switching (lamps, fans, heaters up to ~220W @ 110V)
• Terrarium automation — heat lamp, mister, fan, UV light control
• Aquarium heater and pump control
• Christmas and decorative lighting control
• HVAC zone valve and damper control
• 3D printer heated bed control (12V DC bed — use electromechanical relay instead)
• Escape room and prop automation

Package Contents

• 1 × Solid State Relay Module 5V (1-channel, 100–240VAC / 2A, zero-cross, active-low)

Enjoy free standard shipping on all orders over $199 USD. Orders are processed within 1–2 business days.

Not satisfied? Return any item within 90 days of purchase for a full refund or exchange. Items must be in original condition.

We are committed to quality, reliability, and customer satisfaction. Every product is carefully selected and tested to meet the highest standards.