The signals from this circuit obtained from the 1965 Radio Shack documentation are picked up from a medium wave receiver. L1 and L2 have 80 to 100 turns of yarn 28 on a ferrite rod.
This circuit for very long-time intervals was found in the March 1993 Radio Electronics magazine. Times...
Suggested by National Semiconductor in documentation from the 90s, this circuit uses a switched...
Found in a 1960s RCA manual, this circuit uses components from the era. For the indicated circuit R1 is...