Abstract: The invention relates to the supervision of a measuring circuit which is connected to a load by way of measuring leads. This load is connected to a generator via supply leads. The load is bridged by a resistor. If one of the four said leads is interrupted, the potential on one of the ends of the resistor changes. As a result, a transistor becomes conductive, which implies an error signal. In a preferred embodiment, two transistors are provided, the first transistor being rendered conductive by a voltage difference. The second transistor is rendered conductive either by a voltage difference or by the fact that the first transistor becomes conductive.

Abstract: A DC converter including a transistor switch and a transformer having first and second windings connected so that the transistor passes asymmetrical current pulses to the first winding. When the switch opens, asymmetrical current pulses again pass through the first winding and through a gating circuit connected thereto. The instantaneous voltage across the second winding is used as the drive voltage for the transistor switch to prevent transformer saturation.