This circuit can be used in measurement bridges. We found it in the September 1995 Electronics Now magazine. The meter can be from 50 uA to 1 mA and the power supply is simple.
This circuit, found in a 1958 magazine, is for reference only, since the components are not easy...
Found in Popular Electronics this circuit triggers an SCR and lights an LED when the location of...
This OF-1 LO oscillator was found in a 1980s American documentation. The transistor can be any...