Abstract: A sensor assembly for monitoring an internal condition of a transformer comprising: a body for location outside a tank of the transformer, the body housing an electronics assembly including body sensors coupled to a processor; a probe extending from the body for insertion into a tank of the transformer; a number of probe sensors coupled to the processor disposed at or toward a remote end of the probe for sensing conditions within the tank; wherein the processor is configured to process signals from the probe sensors and the body sensors to produce signals for assessing one or more of: transformer core temperature; transformer insulation state; partial discharge; mechanical state of transformer; chemical state of transformer.

Abstract: A protection device is enclosed. The device has a first MOSFET (Q 10), a second MOSFET (Q 11) and a third JFET (Q 12) with their conductive paths in series with the JFET (Q 12) being located between the MOSFETS (Q 10, Q 11). The source of the first MOSFET (Q 10) is connected to the gate of the second MOSFET (Q 11) and the source of the second MOSFET (Q 11) is connected to the gate of the first MOSFET (Q 10). The MOSFETS (Q 10, Q 11) and JFET (Q 12) together form a variable resistance circuit block connectable between an input and an output The gate of the JFET (Q 12) being coupled to the input and the output by respective current sources.

Abstract: A device which may protect circuits or equipment from overload or transients is disclosed. The device includes a unit consisting of a p-channel FET and an n-channel FET connected with their conductive channels in series and the gate of each transistor coupled to the drain terminal of the other.