Found in documentation from the 1980s, this circuit uses an operational amplifier from that time. Transistors are also from the era, and general-purpose equivalents can now be used.
We found this circuit in an American documentation from the 60's. The transistors are made of...
The accuracy of this circuit depends on adjustments made with capacitors of small tolerances of known...
The figure shows how to implement an OR function with two inputs, using a relay. The relay...