Versatile electronic timer for synchronous switching of multiple electrical devices

An electronic timer consisting of CMOS integrated circuits is described that synchronously switches multiple electrical devices on and off on either circadian or noncircadian cycles. Precision is attained to within 1 min when used in the circadian mode or to within 16.7 msec when used at the highest speed (60 Hz). The electronic timer is useful for behavioral studies, control of environmental chambers, and control of general laboratory appliances.