Electrical control circuits

Claim 1

AN ELECTRICAL CONTROL DEVICE FOR REVERSING THE CURRENT THROUGH A LOAD, COMPRISING: FIRST, SECOND, THIRD AND FOURTH TRANSISTORS, CIRCUIT MEANS FOR CONNECTING THE EMITTER-COLLECTOR PATHS OF THE FIRST AND SECOND TRANSISTORS IN SERIES WITH A SOURCE OF SUPPLY VOLTAGE AND WITH A DIODE CONNECTED BETWEEN THE COLLECTOR OF THE FIRST TRANSISTOR AND THE EMITTER OF THE SECOND TRANSISTOR, CIRCUIT MEANS FOR CONNECTING THE EMITTER-COLLECTOR PATHS OF THE THIRD AND FOURTH TRANSISTORS IN SERIES WITH A SOURCE OF SUPPLY VOLTAGE AND WITH A DIODE CONNECTED BETWEEN THE COLLECTOR OF THE THIRD TRANSISTOR AND THE EMITTER OF THE FOURTH TRANSISTOR, MEANS FOR APPLYING CONTROL SIGNALS TO THE BASES OF SAID FIRST AND THIRD TRANSISTORS, A LOAD CONNECTED TO THE JUNCTION BETWEEN SAID DIODE AND THE EMITTER OF THE SECOND TRANSISTOR, A FIRST COMMON CURRENT-LIMITING ELEMENT HAVING A NON-LINEAR CURRENT-VOLTAGE CHARACTERISTIC CURVE COUPLED TO THE COLLECTOR CIRCUIT OF THE FIRST TRANSISTOR AND THE BASE CIRCUIT OF THE SECOND TRANSISTOR, AND A SECOND COMMON CURRENT-LIMITING ELEMENT HAVING A NON-LINEAR CURRENT-VOLTAGE CHARACTERISTIC CURVE COUPLED TO THE COLLECTOR CIRCUIT OF THE THIRD TRANSISTOR AND THE BASE CIRCUIT OF THE FOURTH TRANSISTOR.