This Power supply sources from 500 to 1,000 mA according the transformar and was found in a publication of the year 1958. The diodes can be now the 1N4004 and the transistor should be mounted on a heatsink.
This “zero crossing detector” was found in a manual of operational amplifiers from the 1980s....
With this circuit it is possible to follow the transmission in the range of 2 meters with a...
This is another possible version of a negative voltage generator using a 555 integrated circuit. The...