Jump start circuit for a vehicle battery

摘要

A jump start circuit (26) for electrical connection between a battery (12) of a motor vehicle and jump start terminals (22,24) in the motor vehicle, the jump start circuit comprising a switch (28) for positioning in an electrical line (18) between one (22) of the jump start terminals and the battery, the switch being biased to a normally open position; and a logic circuit (32) having means for monitoring the polarity of a voltage across the jump start terminals, means for closing the switch on detection of a predetermined polarity, and a timer circuit for opening the switch after closing for a predetermined period of time. Provides protection against incorrect polarity connection during jump starting.