Touch type anti-theft alarm circuit three

It uses the signal generated by touching the sensor piece M with the hand to make the monostable trigger (composed of the 555
time base integrated circuit Ai, resistor Ri, capacitors C2 and C3, and potentiometer RP) work, and drive the switching circuit (composed of
the transistor VT and Composed of resistor R2) and sound analog circuit Az, the speaker B is driven by the power switch integrated circuit Aa to emit
an alarm sound.