This circuit uses a resonant reed switch at the trigger frequency. The circuit is from General Electric in a 1966 documentation. This type of component is rare today.
The circuit shown is from the 1994 Linear Applications Handbook by National Semiconductor. The...
Horizontal output or flyback transformers are no longer used today, as they only appeared on...
We found this voltmeter in a 1977 Radio Shack documentation. The integrated circuit can be the...