This circuit was found in the October 1989 issue of Radio Electronics magazine. It drives an auxiliary relay with the call signal for a possible louder bell.
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...