This alarm oscillator was found in the December 1974 issue of Radio Electronics magazine. The power transistor must be equipped with a good heat sink. The Frequency basically is given by C1.
We found this RF amplifier in documentation from the 1970s. Field effect transistors support...
From different input voltages V, it is possible to reduce the voltage to several fixed values...
This is a typical amplifier circuit for a commercial tape recorder from 1968. The circuit has an...