Scale Expander for 12V Meter (CB21330E)

This circuit was found in a QST from the 1990s. The circuit expands the scale of a 10V instrument to measure 20V.

Low Pass Filter with 741 (CB1454E)
We found this circuit in a documentation on active filters from 1977. The gain of this circuit is...
Simple Touch Switch (CB16945E)
The touch sensor of this circuit consists of a single plate that must be touched to obtain an...
Coaxial Cable Amplifier LM6181 (CB14411E)
The integrated circuit used in this project is not common today, as it was obtained in the Linear...