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.
Using a voltage comparator, we find this AND gate on a Popular Electronics from the 90s. The...
We found this circuit in an old documentation from the 70s. Its purpose is to indicate the...
This circuit appeared in the June 1990 issue of Radio Electronics magazine. Integrated circuits must...