This circuit was found in the January 1996 issue of Electronics Now magazine. The circuit is powered by voltages from 10 to 24 V and has a control for the intensity of the output signal.
Using only one integrated circuit this control was found in an 80's Electronic Engineering. The circuit...
We found this circuit in a 1975 radio amateur documentation. The circuit uses TTL technology and...
The transistors of this circuit found in an English 1980s documentation may be the modern BC548...