Display drive 4029 (CB7555E)

Here we have the way to activate two common cathode displays with 4026 integrated circuits. The circuit for tens and units can be extended.

Torch control (CB7890E)
This circuit was found in an American documentation of the 90s. Optical resources with the LDR as a...
TTL interface with optical coupler (CB25492E)
The figure shows how to couple two TTL circuits using an optical coupler to obtain isolation. The...
Octave equalizer (CB7978E)
Found in Precision Monolithics documentation from the 90's, this circuit equalizes octave signals...