Fuel pump simulation copying circuits found in old school VAG (VW, Porsche etc) motor vehicles.
Top switch represents keyed ignition (+12V). Second switch with voltage source represents running engine with a 12V square wave from a "high energy" capacitor discharge ignition (CDI) (or could be an ECU). Fuel pump motor keeps running if monostable 555 timer keeps receiving a pulse. Input into 555 circuit is modified using a 20nF decoupling cap and dividing resistors for the 12V square wave source. See https://everycircuit.com/circuit/5440951818125312
