We find this circuit in an Electronics Now. The indication of the logic level is done on a 7-segment display according to the connections given in the diagram.
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...