Driving Relays or higher loads with the IO Pi

Created 05/11/2016 | Using the IO Pi Plus or Zero with relays or opto-isolators

The output from the IO expansion boards can drive up to 25mA per channel but to drive higher loads such as relays or some opto-isolators you will need to boost the output using a transistor or mosfets.

The circuit below shows how you can operate a 5V coil relay using either a GPIO output from the Raspberry Pi or using one of the output pins on the IO Pi and IO Pi Zero boards.

Driving Relays or higher loads with the IO Pi

Driving opto-isolators with the IO Pi Plus/Zero

If you would like to connect an opto-isolator to the IO Pi, you can remove the relay and protection diode and connect a series resistor in line with the opto-isolator in place of the relay.

You can use our LED Calculator https://www.abelectronics.co.uk/tools/resistor-led-calc.aspx to find the correct series resistor to use with your opto-isolator.




Products added to basket


Total (inc shipping)

CheckoutView Basket

Free Shipping on all orders over £30

Click to contact us.

Have any Questions?

Send us any questions about this page or product and we will reply within 24 hours.

Submit your Message


Have any Questions?

Thank you for contacting us.

We will respond to your enquiry in the next 24 hours.

You can find answers to many questions and additional product support in our Knowledge Base and the Community Forum.