This circuit was found in an article in Electronics Now magazine from March 1997. The transistors are general purpose, and the indicator is a 1 mA full scale analog type.
This circuit was found in a 1992 publication. The circuit uses common components and includes the...
This protection circuit for battery chargers was found in an old Elektor. The relay is according to...
This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is...