We found this circuit in the July 1990 issue of Radio Electronics magazine. The frequencies are given by capacitors C2 and C3, which can be changed.
This circuit is from Motorola's 1990 Linear Databook. We can implement it with other operational...
August 2017 - Mouser Electronics already has to supply the new Darlington MAAM-011206 Broadband...
This proximity sensor circuit is from an 80's documentation. The used integrated circuits are...