The top switch is the ignition turning on and the bottom switch is the feed from the rev counter (engine running). The capacitor charges up enough to turn on the transistor in about 1 second. This will switch on the FET and current will flow into the load. I intend switching down to 5V to supply USB devices (phone, tablet, etc.)
This allows the engine to be cranked and started before turning on devices. The addition of the feedback holds the power on until all power is removed.
