This simple circuit found in a 1968 EEE was intended for data transmission over the telephone line. The components are from that time, some are uncommon today.
This filter, from an audio publication from 1977, passes the frequency range corresponding to the...
In the figure we have three voltage doubler configurations that can be used in high and low...
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...