This 5 V circuit was found in December 1978 Radio Electronics magazine. The power transistor must be mounted on a good heat sink.
With this circuit it is possible to visualize the characteristic curve of a component on an...
The coil L2 has 64 turns of wire 28 or thinner wire in a 1 cm form coreless and L1 10 turns on L2....
This sensitive touch circuit that triggers an oscillator uses only transistors. The circuit is...