Abstract: A molded case circuit breaker includes a solenoid control circuit for controllably energizing a solenoid to actuate a motor operator to automatically move a handle of the circuit breaker to change the operative condition of the circuit breaker. The control circuit includes a monostable multivibrator that supplies an electrical pulse to the solenoid upon the receipt of a switching initiation signal. The time duration of the electrical pulse is controlled to be sufficiently long to assure proper operation of the solenoid and is determined by a timing circuit coupled to the source of operating voltage for the solenoid. If the operating voltage decreases, the time required to charge the timing circuit increases, increasing the duration of the electrical pulse of the solenoid to assure proper operation under low voltage conditions.