This metal detector using CS209A made by Cherry Semiconductor. The CS209A is a bipolar monolithic integrated circuit for use in metal detection / proximity sensing applications.The CS209A metal detector IC has two on-chip regulators current, the oscillator and low-level feedback circuits, peak detection / demodulation circuit, a comparator and two complementary stages.The oscillator output, along with an external LC network provides controlled oscillations, where the amplitude is highly dependent the Q of the LC tank. The demodulator senses the negative peak of the oscillator wrap and provides a demodulated waveform as input to the comparator. The comparator sets the state of the complementary outputs by comparing the input of the demodulator to an internal reference.The detector is a single coil 100uH. The IC has an oscillator integral part of the strangulation of an external LC circuit is the inductance that is changed by the proximity of metal objects. Is the change in the oscillation that is amplified and demodulated. LED 1 will light and the buzzer will sound when the inductance has changed. Installation is easy: R5 is adjusted with the LC away from any source of metal for the LED lights and buzzer. The control is reversed so that the LED turns off and stops ringing. When the shock comes in contact with a metal object that alters its inductance, LED and buzzer are activated.
