This alarm is either activated or triggered after a certain amount of time, giving the owner time to exit or enter and disarm it. The circuit is from a Radio Electronics from April 1975.
This circuit is from an article in Radio Electronics magazine from August 1972. The circuit is...
Found in 1969 RCA documentation, this circuit maintains constant current in the filament of a lamp...
The integrated circuit used in this application is uncommon today. The circuit is from American...