The speed indication of this circuit is made on an analog instrument. The circuit is used to count pulses (rpm) and was found in April 1976 Radio Electronics magazine.
This circuit was found in a RCA documentation from 1977. The integrated circuit is uncommon today. It is...
We found this circuit in a 1995 documentation. It can measure frequencies from 100 kHz to over 100 MHz...
This circuit was obtained in a Popular Electronics of the 90s. The circuit is compatible with...