8-Channel Solid State Relay

You are currently viewing 8-Channel Solid State Relay
  • Post author:
  • Reading time:4 mins read

Instead of using coil, packaged solid-state relays(SSR) use power semiconductor devices such as thyristors and transistors, which provide a much faster switching speed than the mechanical relays. The Grove – 8-Channel Solid State Relay is based on the high-quality G3MC202P module, which allows you to use a 5VDC to control MAX. 240VAC. With the help of Grove interface, it becomes very convenient to use the SSR with your arduino.

We use an on-board STM32F030F4P6 to control the channels separately. The command from Arduino or other boards is transmit via the I2C interface, the on-board STM32F030F4P6 will parse the command, so that you can control the switch you want.


  • Low power consumption
  • Long lasting
  • Optional I2c address
  • Advantages over mechanical relays:
    • Solid-state relays have much faster switching speeds compared with electromechanical relays, and have no physical contacts to wear out
    • Totally silent operation
    • No physical contacts means no sparking, allows it to be used in explosive environments, where it is critical that no spark is generated during switching
    • Increased lifetime, even if it is activated many times, as there are no moving parts to wear and no contacts to pit or build up carbon
    • Compact, thin-profile SSR of monoblock construction with an all-in-one lead frame incorporates a PCB, terminals and heat sink, which is much smaller than mechanical relays, and can integrate more channels
  • Disadvantages:
    • When closed, higher resistance (generating heat), and increased electrical noise
    • When open, lower resistance, and reverse leakage current
    • Only works for AC laod


Operating input voltage4~6V
Rated Input Voltage5V
Rated Load Voltage100 to 240 VAC 50/60 Hz
Load Voltage Range75 to 264 VAC 50/60 Hz
Load current0.1 to 2 A
Leakage current1.5 mA max. (at 200 VAC)
Insulation Resistance1,000 MΩ min. (at 500 VDC)
Operate Time½ of load power source cycle +1 ms max.
Release Time½ of load power source cycle + 1 ms max.
Storage Temperature-30°C to 100°C (with no icing or condensation)
Operating Temperature-30°C to 80°C (with no icing or condensation)
Operating Humidity45% to 85%RH
Input InterfaceI2C
Default I2C Address0x11 or 0x12
Available I2C Address0x00 ~ 0x7F
Output interfaceDIP Female Blue 2 pin x8
Zero Crosssupport
CertificationUL / CSA


  • Operations that require low-latency switching, e.g. stage light control
  • Devices that require high stability, e.g. medical devices, traffic signals
  • Situations that require explosion-proof, anticorrosion, moisture-proof, e.g. coal, chemical industries.

Hardware Overview

Pin Map


Relay control

K1 is the Relay module, When a 5V voltage is applied between the INT+ and INT-, the relay will be turned on. Then the LOAD1 will connect to the LOAD2.We use a NPN transistors Q1(BC817-40) to control the voltage between the INT+ and INT-.

The CTR is the control signal from the Arduino or other board. It is pulled down by the 10k R2, if there is no signal, the ‘Gate'(port 1) of Q1 will be 0v, and Q1 is turned off, so that the K1 will be turned off. If CTR becomes 5v, then the Q1 will be turned on. INT- of k1 will be connected to the GND of the system, for the K1 there will be 5V between INT+ and INT-, so the K1 will be turned on, and the LOAD1 will connect to LOAD2.

Bi-directional level shifter circuit 

This is a typical Bi-directional level shifter circuit to connect two different voltage section of an I2C bus. The I2C bus of this sensor use 3.3V, if the I2C bus of the Arduino use 5V, this circuit will be needed. In the schematic above, Q17 and Q18 are N-Channel MOSFET 2N7002A, which act as a bidirectional switch. In order to better understand this part, you can refer to the AN10441

Farees Ahmed

The aim of this blog is to serve as a quick reference guide for the Curious. Appreciate your feedback and comments !