This circuit was obtained from an Electronics Design of 1964. The circuit makes use of tunnel diodes that are uncommon today. The circuit works with very weak signals.
Using a 741 op-amp this circuit high-pass to 10 kHz was found in the February 1995 issue of...
Found in 1965 General Electric documentation this circuit applies to a LASCR used as an optical...
Using transistors and lamps, this simple circuit was found in Popular Electronics. The circuit can...