I am trying to toggle an SRD-03VDC-SL-C (3V rated) relay with a Raspberry Pi GPIO.
When I put a wire to the Raspberry Pi 2B ground pin and the other to a 3.3V power pin the relay works (it clicks). I measured 3.28V with my multimeter.
Now, as the relay is confirmed to be working I want to toggle it via software by switching a GPIO pin. I confirmed that the GPIO switching is working with my multimeter: It shows 3.28 V when high and 0 V when low.
But when I connect the wire with the GPIO in high state it does not toggle the relay. How is this possible when both pins have the same voltage and how can I fix this?
Experimenting with the Raspberry I also observed the situation that I could set the voltage to 0 but disconnecting then made a difference. I would assume that in this case disconnecting would not make a difference.