We found this circuit with JFETs in a Radio Electronics magazine from June 1969. The circuit has its assembly described in a complete article. Equivalent transistors can be used.
This automatic battery charger was found in a Popular Electronics from the 90s. The circuit uses a...
The slope of an object causes the sensor, a mercury switch to be triggered. The circuit activates...
The assembly of this circuit was described in an article in the magazine Radio Electronics of June...