This circuit was obtained in a 1964 Electronic Design. The components used are from that time. Observe the high voltage used in the supply.
This circuit, found in documentation from the 1990s, uses a common 7-segment LED display. The...
We found this circuit in an early American 80's documentation. We note that the first gate of the...
Using a V/F converter this circuit was found in the June 1991 issue of Radio Electronics magazine. The...