We found this circuit in a 1973 documentation. The null adjustment trimpot is 10k. The circuit can be powered by symmetrical sources from 9 V. The diodes on the bridge can be 1N4148.
This three-transistor circuit was found in Radio Electronics magazine from May 1969. The circuit is...
This beat frequency oscillator was found in a 1980s documentation. The original FET has a grounded...
With this circuit it is possible to make the selection of transistors and their test according to the...