One of capacitive sensing oscillator circuit burglar alarm


Posted on Mar 28, 2007

By the 555 IC Ai, capacitors Cl, Cz and metal plate (tablet) M distributed capacitance Co and resistor Ri to ground, R2 consisting self-excited multivibrator; the R3-Rs and C3


One of capacitive sensing oscillator circuit burglar alarm
Click here to download the full size of the above Circuit.

~ C5 composition three -order RC integration network; by the CA3130 operational amplifier Az, Re, R7 and RPi, RPz composition comparator; by the transistor VT and R8, R9 composition amplifier. When the body close to the metal plate M, Co capacitance increases, the multivibrator oscillation frequency decreases, RC network outputs a negative pulse, VT conduction, the relay KA pull, turn alarm, an alarm signal. Adjustment potentiometer RPi, RP2, can change the sensitivity of the device.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Digital-to-analog-converters
Power-converter
The Metal Detector Circuit
30 volts panel volt meter using pic mcu
stk4038 bassed 60 watt audio
Bedside Lamp Timers
Odd-ball PI circuit identification request and headroom question
Micropower 1A Boost Converter with Schottky and Output Disconnect
sine wave oscillator
How To Build A Sequential Timer Using A Cmos 4017
Single-ended four-channel amplifier schematic
Radio reception circuit diagram TA31136
Automatic light regulator circuit diagram
Real-time speech recognition system application circuit in family care robot



Top