This repellent operates with frequencies from 30 to 45 kHz, serving for insects and rodents. The circuit is from 80s documentation. The transducer is a piezoelectric type.
The CK722 transistor used in this circuit is one of the first commercial types in the world. The...
This automatic dimmer for incandescent lamps was found in a European publication from the 1980s. The...
This traditional doubler configuration with the 555 can be found in other articles on the author’s site....