This circuit was found in an Experimenters Handbook of the 1990s. The purpose of this circuit is to keep constant the audio signal level of a system, increasing the lower signals.
This circuit maintains on a flashing LED at a frequency determined by the capacitor. The...
After starting, this circuit turns off the relay in a time that depends on the 4020 pulse-count. This...
This sophisticated circuit is from a 1975 documentation. The components are from the time and the...