and s2 2 hours would be closed with the others remaining open if a twelve hour interval were desired switches s4 8 hours and s3 4 hours would be closed and so on to give the desired timing interval anywhere from one hour s1 up to a maximum of 15 hours for the embodiment shown of course the minimum intermit could be smaller by using one or more of the earlier output stages of counter 120 in conjunction with additional diodes and switches longer time intervals could similarly be provided by one or more additional higher count stages so long as at least one of the outputs q11 through q14 whose corresponding switch s1 through s4 is closed is at a logical low signal the alarm will not sound the alarm will sound only when all of the outputs q11 through q14 whose switches are closed go to a high logic level when switch 112 is closed a timing interval is begun counter 120 begins to accumulate counts from the oscillator but until the selected count as determined by the position of switches s1 s4 is reached the alarm will not be energized during this interval one or more of the selected outputs q11 q14 will be at a logical low level thus establishing a current path from v.