Circuit Design Help

[Alan Anderson]

Originally Posted by Ronald_raygun

...I wasn't sure where to put the normally closed momentary switch...Is there anything wrong with this circuit?

The purpose of that switch is to interrupt the power to the relay coil and permit it to turn off. It should be placed between the Normally Open relay contact and the coil. It would also work if placed between "+" side of the fuel cell and the common relay contact, or if placed between the other side of the coil and the "-" side of the fuel cell.

By the way, I'm a little confused about what the "fuel cell" actually is. You're describing it as something which needs to be charged from an external electrical supply, but my understanding of a fuel cell is that it uses chemical fuel to produce electricity, and gets "charged" by filling it with hydrogen or alcohol or some hydrocarbon.