This circuit was found in an American 1980s documentation. It analyzes the exhaust gas of a vehicle using a special sensor. The indicator is a milliamperimeter.
The battery charger suggested in the figure has its current limited by resistor R1. This component can...
The operation of this circuit is not common today, but equivalents can be experienced. The circuit is...
This circuit generates various types of sounds and can be used as a toy. The circuit is from Radio...