I have a question regarding the usage of a CD4066 bilateral switch. I want to know if it is okay to use the switch to switch a completely different circuit without attaching any kind of ground or anything to the other circuit. Basically, I'm trying to override a switch in a door lock circuit. I don't know what kind of voltage is being switched by the existing switch, but I do know that it is a battery powered circuit supplied by a 9v battery. Here are the connections I am figuring for the 4066. Pin 1/Pin 2 - Wires to either side of the existing switch on the other circuit (these are the only connections I want to make to that circuit) Pin 7 - Ground from uC side Pin 14 - +5V DC from uC side Pin 13 - uC pin with 1k pulldown. I'll pull this up in software when I want to close the switch. Is this okay, or will I run into issues? I've been using a ULN2003 with a relay to perform the same job, but I would rather use the 4066 to reduce the power requirements (keeping the relay closed for too long zaps the batteries in my circuit too fast). Thanks for any help.