This circuit was found in a Poptronics of the 90's. The components can be changed to the desired frequency. The power supply must be symmetrical.
The current of this charger is determined by Rs. The circuit is from the 1982 SGS linear...
This circuit is used to connect an additional capacitor to a tuned circuit of a VFO. The circuit...
This alarm does not interrupt its operation when the power is cut. A battery is kept at a constant...