Found in a Westinghouse Silicon Power Handbook from the 60s, this circuit makes use of period components. Special high voltage transistors are used. Zeners are 15 V.
This alarm, from a 1996 magazine, can be fitted with two BC548s in the original configuration...
Using only one general purpose transistor this circuit is powered by batteries. The lamp of the...
Can be used as a shield, this old American documentation circuit offers digitally selected...