We found this version of the automotive tachometer in a 1980s publication. Variations from other sources appear elsewhere in this section. The indicator is a 0 to 1 mA milliammeter.
In the figure we have a very low current DC to DC converter using a 555. The circuit can have...
This circuit was found in a Japanese documentation of the 70's. It uses transistors of the era and is...
This interesting circuit of a 1988 documentation consists of a mouse trap where the sensor is left to...