I’d like to use the Pololu Basic SPDT Relay Carrier with 12VDC Relay in a completely analog project and have a switch activate the relay. Is it possible to drive the EN pin when a switch is turned on? For example, use the switch to send 12 VDC to the EN pin?
As mentioned and shown in the schematic on the relay carrier’s product page, the control signal is fed directly to the gate of the BSS138 N-channel MOSFET. According to the BSS138 datasheet, the maximum gate-source voltage is 20V, so you should be able to send 12V directly to the EN pin with a switch to actuate the relay.