This circuit, with printed circuit board included, is from a Radio Electronics magazine from July 1971. The SCR can be any equivalent of the 106 series.
This circuit was obtained from a Poptronics in June 2001. The magazine no longer exists, but the...
We find this circuit in a 1980s documentation. The circuit uses uncommon components today which can...
This circuit has a very high input impedance and a very low output impedance. We found it on a...