This game was found in an old Popular Electronics. The unijunction transistor can be 2N2646. The supply can be done with voltages from 6 to 12 V.
The phototransistor of this alarm can be of any type. The relay must be sensitive type according...
This power supply can supply voltages of 6, 9 or 12 V depending on the zener used. The maximum...
This oscillator with common general-purpose transistors appeared in Radio Electronics magazine in...