This circuit allows you to read resistors up to 20 M ohms, converting it into voltage. The circuit is from the 90s. The operational ones used admit modern equivalents.
This 555 circuit was found in the October 1992 issue of Radio Electronics magazine. A power stage...
This circuit was found in a 1980s documentation, using a comparator from the time. The...
Suggested by Motorola in a 1992 documentation, this circuit works as a remote volume control,...