A pyroelectric infrared body sensing switch circuit, comprising:
- a power unit comprising a first power circuit and a second power circuit, each power circuit comprising a voltage reducer, a rectifier, a filter, and a voltage stabilizer, the second power circuit further compring a positive pole and a negative pole;
- an infrared detection circuit comprising one or more pyroelectric infrared detection elements;
- an amplification circuit;
- a delay unit comprising:
- a delay unit time base circuit comprising a trigger end, a discharge end, and a threshold end;
- a delay unit monostable circuit comprising external components and a delay unit amplification triode, the delay unit amplification triode comprising a base, a collector, and an emitter;
- and a monostable circuit equipped with an RC charge subcircuit to control delay time, the RC charge subcircuit comprising a charge capacitor and an amplification triode comprising a collector and a base;
- an execution unit;
- a plurality of amplification resistors;
- a discharge diode;
- a comparator circuit comprising an output;
- and
- a trigger subcircuit comprising:
- a trigger current limiting resistor;
- a trigger NPN switch triode comprising a base, an emitter, and a collector, the emitter of the trigger NPN switch triode connected to the negative pole of the power supply through the trigger current limiting resistor, the base of the trigger NPN switch triode connected to the output of the comparator circuit;
- a trigger capacitor comprising a positive pole connected to the collector of the trigger NPN switch triode;
- and
- first and second trigger resistors connected in series with the trigger capacitor and connected across the positive and negative poles of the power supply, the trigger NPN switch triode, and the trigger current limiting resistor, wherein:
- each of the first power circuit and the second power circuit receives AC power from an AC power supply and supplies DC power through RC voltage reduction by the voltage reducer, full-wave rectification by the rectifier, filtration by the filter, and voltage stabilization by the voltage stabilizer,
- the first power circuit supplies power to the execution unit and the second power circuit supplies power to the infrared detection circuit, the amplification circuit, and the delay unit,
- a first signal outputted from the infrared detection circuit is inputted to the amplification circuit,
- a second signal outputted from the amplification circuit controls the activation of the delay unit,
- a third signal output from the delay unit controls the execution unit,
- the first signal outputted from the infrared detection circuit comprises superposed output signals from the one or more pyroelectric infrared detection elements,
- the charge capacitor of the RC charge subcircuit is connected in parallel across the collector and the base to form a charge bypass of the charge capacitor,
- the collector and emitter of the delay unit amplification triode are connected across the discharge end and threshold end of the delay unit time base circuit and the negative pole of the second power circuit, respectively,
- the collector of the delay unit amplification triode is connected to the positive pole of the second power circuit through the plurality amplification resistors,
- at least one of the plurality of amplification resistors also acts as a resistor in the RC charge subcircuit,
- the charge capacitor is connected in parallel across the collector and base of the delay unit amplification triode,
- the discharge diode is connected in parallel across the base and the emitter of the delay unit amplification triode,
- the trigger subcircuit connects the amplification circuit and the delay unit, and
- the first and second trigger resistors are connected at a connection point, and the connection point is connected with the trigger end of the delay unit time base circuit such that an output signal from the amplification unit controls the operation of the delay unit.