The LED frequency flashes depends on the value of the capacitor tested according to the table. We found this circuit in a Popular Electronics from the 80s.
Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of...
We find this circuit in a 1980s documentation. The circuit can be applied to modern operators with...
January 2017 - New ROHM TFZV series of zener diodes is now available from Mouser Electronics. The...