Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic recording of telephone calls. The circuit was used with old cassette recorders of the time.
This circuit allows the measurement of very weak currents indicated on an analog instrument or...
Found in National Semionductor documentation this circuit combines a tone control with an...
Found in a 73 magazine from the 1980s, this circuit generates signals from 3.2 to 22 MHz. FETs can be...