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.
Found in a 1964 General Electric documentation, this circuit uses PUTs that are not currently...
This double tone generator uses a specific integrated circuit, having been found in a 1977 CMOS...
Found in American documentation from 1968, this circuit has an acute cut-off of the frequency to...