Found in Philips documentation from 1968 this circuit operates at frequencies up to 10 MHz with 76 dB gain. The double transistor can be replaced by a matched pair.
This circuit was obtained from a 1978 Practical Wireless. It generates a low frequency, low...
In the figure a circuit that is the basic application of NE567 for the detection of a tone applied to...
Found on an 80's Radio Electronics, this circuit is designed to pass the 300 to 34,000 Hz voice...