E ; C Ultrahigh Precision High Accuracy Resistors. E ; C RU types are ultra high precision high accuracy resistors. These precision resistors have a higher reliability when mounted on board and they also offer long-term stability. They are small and lightweight, strong resistance for pulse voltages. Small temperature coefficient and small resistance tolerance. Operating temperature range is -55°C to +150°C. Applications. Semi-conductor equipment X ray apparatus Measuring instruments