This oscillator for the fifth overtone of a crystal was found in a Radio Electronics magazine from May 1970. Transistors are RF types, and the transistor determines the maximum frequency achieved.
The power transistor of this circuit can also be the TIP42 mounted on a good heat sink. The...
Using a window comparator, this circuit trips over a certain range of input voltages. Formulas for...
This timer circuit was found in a 1980s documentation. The integrated circuit is the 555, which...