WARNING CIRCUIT FOR FIRE FIGHTER

摘要

PURPOSE: Provided is a warning circuit for a fire fighter which displays residual of compressed air in a vessel for the compressed air by a naked eye so that it enables the fire fighter to perform fire fighting and rescue work safely. CONSTITUTION: The warning circuit for the fire fighter comprises the parts of: a power part(A) wherein two batteries are connected to a switch for selecting batteries to supply power for each circuit part and certain voltage is supplied into a circuit part(B) for measuring residual of the compressed air through a constant voltage IC; the circuit part(B) for measuring residual of the compressed air which measures pressure of a compressed air box by a load cell and an operating amplifier(OPA) to produce pressure as voltage, supplies for an input part of a second IC through a diode for preventing reverse voltage(D1) to compare input voltage and emits its status for enabling to check residual of the compressed air visually; a detection circuit part(C) which changes resistance into LOW state, blocks the current of an emitter in a transistor(TR3)(TR4) and works a relay(RY1) to supply power for a buzzer circuit part(D) when two mercury location sensors(A)(B) are worked; the buzzer circuit part(D) which works a buzzer IC, sends an intermittent buzzer signal into an output transistor(TR5) and rings the amplified signal through an output transistor for ringing the buzzer; and a circuit(E) for guarding the batteries which lights a luminous diode for guarding batteries(LD1) and warns the life span of the batteries visually when the batteries are lowered under reverse voltage of a constant voltage diode.