This circuit is from documentation from 1965. However, it can be created with modern transistors. Power comes from two 9 V batteries.
We found this circuit in the June 1992 issue of Radio Electronics magazine. The sensor is a common...
This circuit converts a positive CMOS supply voltage to a negative one. We found it in a 90s...
This tone control was obtained from the CA3140 datasheet, originally created by RCA. The CA3140...