Fuel pump simulation copying circuits found in old school VAG (VW, Porsche etc) motor vehicles.
Top switch represents keyed ignition (+12V). Second switch with square wave voltage source represents running engine as a +30V "spike" from primary side of ignition coil. Fuel pump motor keeps running if monostable 555 timer keeps receiving a pulse. If the engine stops (no more ignition spikes) then the fuel pump safely stops running.
