This 4 Relay Module needs a power supply of 5VDC. The opto-insulated inputs can handle 3-24VDC control voltage, with a maximum input current of 22mA at 24VDC.
A jumper can switch between 2 modes:
1. If the jumper cap is set to VCC and JD-VCC, relays and optocoupler inputs are using the same 5VDC power supply.
2. If the jumper is open, a separated 5VDC power supply can drive the relays and the inputs are open for voltages up to 24VDC.
The inputs are LOW-active. It means the output of a microcontroller (like Arduino or Raspberry) draws the input current to GND. The LOW level activates the relay, and a high level (or 3-state level) deactivates the relay.
Other relay modules with 2 relays and 8 relays are also available.
High-Current relay modules (30A) are available as well.
Finally, we offer relay modules for the ESP-01 IoT module, WeMos D1 Mini, stackable I2C Arduino relay shields, and a WiFi 4-Channel relay DIY kit.
Bruce MacDougall (verified owner) –
This is a reliable relay board. I have several in use 24/7 for several years without issues