This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is intend to receive MW station and the transistors are germanium types not easy to find today.
Only incandescent lamp can be used in this circuit. The SCR must be mounted on a heatsink and...
This frequency modulated light transmitter is from a 1990s documentation. The circuit may use...
This sole beacon which has a battery charged by photocells was found in documentation from 1991....