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.

Oscillator up to 50 MHz (CB23739E)
The frequency of this oscillator depends on the crystal used and the transistors. The circuit was...
MOSFET Stage (CB25576E)
This circuit shows how to use the 4007 MOSFETs in an amplifier stage. We found it in an...
Touch Sensor (CB18350E)
This circuit was found in a 1967 Japanese documentation. It consists of a touch control system with...