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 makes it possible to reverse the direction of a DC motor through a relay controlled by a...
The A3906 integrated circuit from Allegro MicroSystems (www.allegro.com) consists of a single...
In the circuit of the figure, when pressing S1 the sound varies according to the value of R2 and...