This circuit can be used as an answering password system in a store, office, or other location. The circuit is from Intersil using components of the time. The circuit is from the 80's.
We found this relaxation oscillator in a 1967 General Electric documentation. The frequency is given...
This circuit was found in the September 1984 issue of Radio Electronics magazine. The circuit has...
Although the BD135 transistor is not specifically for RF applications, some of them can easily...