Knowledge Base
The AB Electronics UK Knowledge Base provides support solutions, tutorials and troubleshooting guides.
Driving Relays or higher loads with the IO Pi Plus
Using the IO Pi Plus or Zero with relays or opto-isolators
The IO Pi Plus expansion board can drive up to 25mA per channel, but to drive higher loads, such as relays or some optoisolators, you will need to boost the output using a transistor or MOSFETs.
The circuit below shows how to operate a 5V coil relay using either a GPIO output from the Raspberry Pi or one of the output pins on the IO Pi and IO Pi Zero boards.
Driving optoisolators with the IO Pi Plus/Zero
Suppose you would like to connect an optoisolator to the IO Pi. In that case, you can remove the relay and protection diode and combine a series resistor in line with the optoisolator in place of the relay.
You can use our LED Calculator https://www.abelectronics.co.uk/tools/resistor-led-calc to find the correct series resistor for your optoisolator.
Related Expansion Boards
32 channel MCP23017 digital I/O expander for the Raspberry Pi
32 channel digital I/O expander for the Raspberry Pi
Related Articles
Using the IO Pi interrupts with the Raspberry PI GPIO interrupts
Reading the GPIO pins on the IO Pi Plus using MQTT Message Queue Telemetry Transport
Control the GPIO Pins on the IO Pi Plus using the MQTT Message Queue Telemetry Transport
Using the IO Pi Plus or Zero with relays or opto-isolators
