We found this circuit in an American publication from 1977. The circuit drives two LEDs according to the control of the inputs. The technology is TTL requiring 5 V to power supply.
This S-meter circuit was found in a 1976 publication. The circuit is used to measure the signal...
The components of this filter are calculated using conventional formulas (see mathematics section of...
This is a Japanese commercial radio from the 60s. The superheterodyne circuit of 7 transistors for medium...