Simple circuit to make Glow an LED without physical wire connection. It provides Energy to the LED in the basis of Inductive Coupling, wireless transmission of Electrical energy happening here through Magnetic flux coupled coils.
Construction and Working
This circuit constructed as two parts one in Energy transmitting Circuit another one is Receiver circuit with single LED. Here Tx-Coil is made by 30 SWG (Standard Wire Gauge) Enameled copper wire with 6CM dia 15 turns + center tap + 15 turns. The Rx-Coil is also made by the same kind of Enameled copper wire with 6CM dia 30 turns.
The 2N3904 is a NPN Bi-Polar Junction transistor used for low power Switching purpose. Bias applied (1.5V) to the transmitter coil center tap terminal and the transistor Q1 makes it as high frequency Switching pulse, due to this process Tx-coil gets Energized and makes alternating Magnetic field.
Near by Rx-Coil receives magnetic flux and makes Inductive coupling hence it induce flow of current/voltage and LED starts glowing. This Receiver circuit works around three inches from the transmitter circuit. If you use single LED at receiver then don’t increase transmitter circuit bias than 1.5V.