We found this circuit in the Electronics Experimenter Handbook magazine from 1993. L1 has 2 = 2 turns of 28 or 30 wire in the shape of 0.5 cm without core. The range reaches a few tens of meters.
This circuit was found in an American documentation from the 90s. It can be implemented with...
This amplifier for the experimenter´s bench source 1 W and uses germanium transistors but can be...
This sensitive touch circuit that triggers an oscillator uses only transistors. The circuit is...