Adjustable reference (CB21540E)

We found this circuit with 5.3V zener in a Philips publication from the 60s. The op amp could be a modern equivalent.

Integrated AM Radio (CB20268E)
This circuit that uses potentiometer tuning, was found in a documentation from the 80's. The...
Ignition for cars with positive ground (CB23628E)
Another electronic ignition circuit for cars with positive ground. This circuit is from a Radio...
Biquad Filter MC4741 (CB14466E)
The MC4741 integrated circuit consists of four operational amplifiers similar to the 741 in a...