This circuit is from documentation from 1965. However, it can be created with modern transistors. Power comes from two 9 V batteries.
This circuit works with only 1.5 V and can be powered by a solar panel. The circuit is from 1991....
This digital timer provides timings from 1 minute to 10 hours with indication on a 3-digit...
This sensitive Japanese mid-wave receiver from the 1960s has an output power of 45 mW and is...