This circuit was found in the July 1998 issue of Electronis Now magazine. It is a traditional gated version of the 4049 and has its frequency controlled by R2.
This well-known configuration was found in a 1982 publication. Other operational amplifiers can be...
Suggested by General Electric in 1965 documentation this circuit is intended for the 120 Vac...
Combined with the two previous circuits, we can create a simple multimeter with this circuit. The...