This circuit was found in a Radio Electronics from February 1966. The circuit operates with a common battery and the frequency is given by the resonant LC circuit.
This circuit provides a signal of higher frequency the greater the intensity of the light incident on...
This circuit was obtained from a 1978 Practical Wireless. It generates a low frequency, low...
This circuit can be used as a lockable shield. A pulse activates the relay that remains on even...