This circuit was found in Philips documentation from 1965. No information was given about the transformer. Transistors are from the era.
Although indicated in the original publication of the 1980s as a capacitance switch, the circuit...
This amplifier step with a transistor has an input impedance of 100k to 10 M. The transistor can be any...
This circuit was obtained from an English magazine from 1977. The magazine no longer exists, but...