FIELD: electronic circuits using pulse-width modulation for solenoid excitation. SUBSTANCE: solenoid is connected in series with transistor and sensing resistor. Voltage drop across resistor is compared with reference value to check solenoid for overloading. Circuit depends for its operation on principle of periodic repetitive time intervals; solenoid carries current in the beginning of each time interval irrespective of whether it is overloaded or not. If overload has been detected during time interval, then during next time interval current through solenoid is cut off upon completion of initial interval in particular window. On the contrary, if overload has not been detected during time interval, current is allowed to flow during next interval. In addition, there is feedback circuit to detect open circuit in solenoid winding at the end of one of time intervals upon expiration of a number of such intervals. EFFECT: provision for limiting current carried by solenoid winding and for detecting open circuit in solenoid coil. 1 dwg
