R1 may be 10k and R2 100k. The transistor can be the BC548 and instead of the small lamp we can use a series LED with a 1k resistor. D1 is germanium and C1 is 10 nF. C2 can be 47 nF.
We found this circuit in a 1982 documentation. The circuit drives a relay when the sensors are...
I found this circuit in an Electronics Handbook from 1989. The circuit can be assembled with a...
This circuit was taken from old American documentation. The transistors used make it possible to...