This circuit has its application suggested in an alarm system. The circuit is from an old RCA manual. R1 has 5.6 ohm, R2 22k, R3 2k2. The capacitor is 8 uF.
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...