This circuit was found in the February 1994 issue of Electronics Now magazine. The circuit uses 6 and 12 V regulators that must be equipped with heat sinks. The current is 1A (max).
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...