This tone control was obtained in a Signetics documentation of the 90s. The integrated circuit can be practically any operational amplifier. The power supply is symmetrical.
This circuit was obtained in a technical publication from the 1970s. It fires a diac and thus a...
This circuit has a very high input resistance to excite a 0-1 mA indicator instrument. The FET...
With this circuit it is possible to use a common hair dryer as a hand dryer. The circuit is timed...