mains wiring locator

E ig mains wiring locator The accompanying circuit shows a 9V simple means of locating current- carrying conductors. The detector coil is a telephone pick-up with suction pad. The magnetic field of a current- carrying conductor induces a very small voltage in L1that is amplified in opampsA,andA2.Capacitors C2. . C5have a value which ensures maximum amplification in A, and A2 of signals around 50 Hz. Diode D1will light during positive halve-waves of the mains current. 9V C4 9V R3 R40C3R6 C5 —II R1 R7 A3 CLOD 1N4148 D2 10n 10n lon 710p 16V 16V 85496 Al ,A2,A3 = % IC1 = LM 324 7-59