Abstract:
A system of having a circuit having an electrical coil configured to generate a magnetic field based on properties of a surrounding space and an object presented to the electrical coil and a sensor configured to sense inductance and resistance of the electrical coil and to discriminate the object presented to the electrical coil in accordance with the sensing. A precision variable resistor to control resistance of an in-loop photoresistor with an out-loop photoresistor that are located parallel to each other.