This circuit is an alternative version of the previous one also found in the July 1995 Electronics Now magazine. The triac must be equipped with a heat sink.
This alarm from an old 1978 publication uses PNP transistors and driver and output transformers that are...
If the reader still uses silk screen printing tables this is an interesting circuit found in a 1994...
We find the original circuit in a technical publication of 1978. Changing the components, such as...