This circuit was found in a documentation of the time. It consists of a receiver with two RF stages for the medium wave band. The audio power is on the order of 2 W.
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...