This power source was found in a 1968 Electronics World. The transistors are from that time. The current of each output is limited by the transformer.
This low-pass filter was found in an American publication from the 80's. The circuit uses an...
This continuity tester for low resistances was found in an English magazine from 1978. The circuit...
This low-pass filter with 741 op and symmetrical source was found in the August 1993 issue of...