This circuit was found in a 73 magazine for radio amateurs of the 90s. The circuit uses two types of indicators, the diodes are for general use. The power supply is 5 V.
This adjustable source was found in a 1979 documentation, but all components are still common...
September 2016 - It can be obtained from Mouser Electronics the new inductors for power supply of...
E) The interesting thing about this circuit found in a 1985 English magazine is that it controls the...