When
you walk through with metal in your pocket, the impedance of the
circuit changes – resulting in significant change in current in the
circuit This change in current is detected and the electronic circuitry
causes a sound to be emitted as an alarm Rationalised 2023-24
Physics
194
7 8  TRANSFORMERS
For many purposes, it is necessary to change (or transform) an alternating
voltage from one to another of greater or smaller value