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.
The circuit below is found in the manuals of several manufacturers in the LM123 series of...
The integrated circuit used in this 70's project is unusual, being the critical element of an...
We found this circuit in Radio Electronics magazine from May 1967. The circuit has the tuned...