3 Sets DIY Pyroelectric Infrared Sensor Kits Anti-Theft Circuit Electronic Technology Training Sets

Description Size 82 x 44mmTexture of material Two sided 1 6mm FR 4 boardLong life Low ESRFunction Pyroelectric infrared sensor security circuit consists of pyroelectric infrared sensor PIR integrated operational amplifier LM358 voltage comparator LM393 110 alarm circuit and boot delay circuit etc The circuit can be used as home security When the family leaves the room the switch K1 is closed the circuit starts to work As long as someone enters the room after a period of time it will sound alarm 1 The circuit is energized the pyroelectric infrared signal of infrared sensor PIR to detect the front radiation of human body from the signal PIR 2 feet output weak after amplification transistor VT1 through the C2 input to the op amp IC2A 3 foot high gain low noise amplifier and then by IC2A the 1 foot output signal 2 IC2B in the circuit as a voltage comparator its 5 pin voltage reference is provided by R10 VD1 IC2A when the 1 foot output signal to the IC2B 6 feet 5 and 6 foot input voltage is compared if at this time the 6 foot voltage ratio 5 feet high 7 feet of IC2B from high level to low level The C6 through the VD2 discharge the IC3 2 feet into low level if the voltage reference voltage of 2 feet than 3 feet of a resistance R14 partial pressure of R15 with low IC3 the 1 foot into a high VT2 transistor conduction music chip IC4 the 2 foot voltage output audio signal after amplification transistor VT4 buzzer driver BELL issued 110 alarm sounds 3