Found in a 90s Popular Electronics, this circuit uses general-purpose transistors, serving to indicate the polarity of circuits.
Line voltage compensation (CB8816E) This circuit for the alternating current line (AC line) was...
This circuit was obtained in a 1982 English magazine of 1982. This circuit has three external...
This circuit is based on the operational amplifier LM833 which is not a common component today. The...