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.

Linear Ramp Generator MC1455 (CB14585E)
The integrated circuit used is equivalent to the 555 and the transistor can be the BC558. R1 and...
Standing Wave Ratio Meter (CB13999E)
We found this circuit in issue 10 of the Italian magazine Selezione Rádio of 1982. The circuit...
Parallel Port Shield (CB17121E)
This circuit is from 1997 documentation, a time when the parallel port was the most common means of...