In fact, this circuit from the 60's applies to photographic printers of the time, timing the lighting of a 20 W lamp. The components are from the period.
We found this trebble booster circuit in a 1990 documentation. The components are current, and the...
This circuit was found in an 80s Hands On Electronics. It senses the water level in a reservoir by...
This circuit was found in General Electric documentation from the 1980s. The circuit is intended...