We found this circuit that converts a direct voltage into a proportional frequency signal. The circuit is from an Electronics Now from April 1993. The JFET can be of any type.
Found in a Motorola documentation from 1965, this circuit consists of an electronic ignition with a...
This Linear Technology circuit can measure currents from 100 pA to 100 uA. The circuit is from the...
With this circuit it is possible to select the upper or lower side band on an SSB transmission by...