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4 Channel Opto Isolated Relay Module

This Wiki page contains additional information for the MOD-RELAY4-5V-10A-T2 from Modtronix.

For safety reasons we DO NOT recommend using this module with voltages above 12V. Any use of this module is at your own risk! Always take necessary safety precautions when working with high voltages to prevent electrical shock! We will take no responsibility for any damage, personal injury or death incurred due to using this unit with high voltages!

This modules contains 4 relays, rated at 5V and 10A. Each relay has a LED indicator. It can be used to control various appliances, and other equipment with large current. It can be controlled directly with 5V logic signals from a microcontroller (Arduino, 8051, AVR, PIC, DSP, ARM, ARM, MSP430, TTL logic).

Each relay has an Optocoupler, providing optical isolation. Each relay also have a freewheeling diode protection.

This module has a 6 pin header(standard 2.54mm pitch) for connecting power (5V and GND), and controlling the 4 relays. These pins have the following functions:

  • IN1 to IN4: Controls relays 1 to 4, active Low! Relay will turn on when this input goes below about 4.2V
  • GND: Connect 0V to this pin. Is used to power the board (optocouplers and relays).
  • VCC: Connect 5V to this pin. Is used to power the board (optocouplers and relays).
Front View
Back View


  • Channels: 4 Relays
  • Relay Voltage: 5V
  • Relay Coil Current: 72mA at 5V per relay
  • Relay Output Current: 10A at 250VAC, 10A at 30VDC
  • Board Supply: 5V supply voltage
  • Input Type: Opto Isolated inputs
  • Power LED: 1 LED for power indication
  • Channel LEDs: 4 LEDs to indicate state of each relay
  • Module dimension: 54.5mm x 77.2mm


The schematics can be downloaded here.

products/modules/relay/mod-relay4-5v-10a-t2.txt · Last modified: 2017/02/17 01:22 by modtronix