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.
Found in a Popular Electronics from the 90s, this circuit makes use of an unusual integrated...
Found in a 1969 documentation, this neon lamp circuit may have the number of steps increased. The power...
Found in American documentation, this circuit can make use of modern equivalent transistors. The...