This circuit found in a 1964 US publication reverses the signal level by providing 9 to 0 V outputs from 0 to 9 V signals. Transistors may be equivalent.
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...