Obtained in an Electronic Design from 1968, this circuit has the voltages determined by the zener diodes. Transistors can be modern equivalents.
We found this 3-transistor receiver in the July 1970 issue of Radio Electronics. The transistors may be...
This circuit matches a source of high or medium impedance audio signals with a low impedance...
Obtained in a 1969 Ferranti documentation, this circuit dissipates only 2.2 mW with 4.5 V. The...