This circuit is from a Popular Electronics from the 90's. The audio amplifier admits equivalent. The others integrated are not very common today.
I found this circuit in a 1998 publication, but as all components are common, it can be easily...
The circuit shown in the figure can be used as an indicator of presence and high voltage in a...
The LM381 integrated circuit is not very common today. The circuit is from an old publication, but it can be...