This circuit was found in a 1967 Electronics World. We can design it with a BF245 for the FET and a BC558 for the bipolar transistor. The circuit has 3 scales and a 10 M ohm input resistance.
The circuit shown in the figure is suggested by Intersil (www.intersil.com) and makes use of the...
We found this version of the automotive tachometer in a 1980s publication. Variations from other...
The battery charger shown in the figure uses two 60 W incandescent bulbs in series to limit the...