This untuned circuit uses one of the world's first commercial transistors, the CK722, having been found in a 1966 publication. Equivalent modern types can be used.
This circuit has its battery charged by a solar system. The circuit uses components that admit...
This triac phase control circuit uses an integrated circuit not very common today. We found this...
This amplifier was found in an old publication of 1990. With the changes, it may still be...