Gain 10 Voltage Amplifier (T456E)

This 4-stage circuit has a voltage gain of 10 and negative feedback. The circuit was found in an old MIT publication.

AC Probe (CB16355E)
A neon lamp and a resistor are all you need to determine the live and neutral pole of an outlet,...
Undervoltage Indicator (CB4988E)
This circuit indicates when the monitored voltage drops below the value determined by the divider...
Multifunction Timer (CB18763E)
We found this sophisticated timer with several functions in a 1993 publication. The circuit can be...