Found in a 1968 American documentation, this circuit uses an operational amplifier that is uncommon today. The feed must be symmetrical. The gain is 40 dB.
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...