4 Channel Relay Module (HCARDU0025)

Relay modules designed for interfacing to microcontrollers.
Post Reply
Site Admin
Posts: 748
Joined: Sun Aug 05, 2012 4:02 pm

4 Channel Relay Module (HCARDU0025)

Post by admin » Wed Dec 05, 2012 5:51 pm



5V 4-Channel Relay interface board;
Equiped with high-current relay, AC 250V 10A / DC 30V 10A;
Standard interface that can be controlled directly by microcontroller (Arduino , 8051, AVR, ARM etc.)
Contol pins protected with opto-isolated circuit


Control various appliances, and other equipment with large voltage/current


    IN1............DIO for relay 1
    IN2............DIO for relay 2
    IN3............DIO for relay 3
    IN4............DIO for relay 4
COM pin is connected to the cathode of all 4 opto-isolators. For normal operation this should be connected to the adjacent GND pin via supplied jumper.


Can I connect this module to the 3.3V digital IO pins of my Raspberry Pi, Due, etc...?

The module should be safe to connect 3.3V development boards that do not have 5V tolerant DIO. Although the module is powered from a 5V source, each of the digital 'IN' pins are connected in series to an opt-isolator and an indicator LED. Due to the forward voltages required by the opt-isolator LED and the indicator LED to allow them to conduct, you should only see about 3V at the IN pins when they are not grounded. The only thing to check is when energising the relays by grounding these pins there will be about 2-3mA of current flowing into each DIO pin. You should check that your development board's IO cells are capable of sinking this amount of current which in the case of this 4 channel relay will be between 8 to 12mA when all relays are in the energised state (IN1 2, 3 & 4 low). For an Arduino due this is fine, but for a Raspberry Pi, this is software configurable and depends on it's source/sink DIO current setting.

How do I power the module?

The module requires a 5V supply which should be connected to right most pin marked VCC for positive, and GND for negative (0V). There is a small tolerance for this supply which is limited by tolerance of the relays of ~ 4.4V to 5.5V.

What is the JD-VCC pin for?

This pin should have a jumper on it connecting it to VCC by default. It is simply there to provide the option of separating the 5V supply to the relays so they can be powered from a separate isolated power supply.

How do I energise the relays ?

Applying GND to either of the IN terminals should energise the appropriate relay (power to VCC and GND must also me connected of course). Disconnecting the pin or pulling the pin to 5V will de-energise the relay.

Post Reply