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.
Other CMOS gates can be used in this sensor, which we found in the July 1995 Electronic Now...
This circuit is from the American magazine that no longer exists Science & Electronics,...
Using the 4046 PLL we found this circuit in the December 1989 Radio Electronics. The circuit...