We found this frequency meter circuit in a 1974 documentation. The circuit is powered by 12 V and has 8 digits. Changes can be made using a prescaler to reach higher frequencies.
This circuit is from an old manual of operational amplifiers. The setting can be adapted to work...
The operational amplifiers used on this Motorola circuit from the 1970s are no longer common, but...
This circuit uses a feedback system that latches the relay when closed. The circuit uses an...