DETAILED DESCRIPTION OF THE INVENTION

Referring to Fig 1, the device has two “sides”: equipment side and surge side. The device consists of an array of semiconductor protection devices on the equipment side connected to the device being protected via some form of connector. These semiconductor devices are themselves protected by an isolation /coupling transformer. This transformer is then connected to the “surge side” and cable via another connector. Gas discharge tubes are installed on the surge side of the device. 

The advantage to this design verses the more traditional design is that the semiconductor surge protection devices and the equipment being protected are isolated by an isolation/coupling transformer which blocks a majority of the surge energy before it can reach the more sensitive semiconductors and even the equipment itself. It does this because lightning induced voltages and most other static inducted voltages take the form of common mode voltages which do not pass the isolation/coupling transformer and the isolation/coupling transformer is, for the most part, immune to damage from these kinds of surges. The greatly reduced voltages/energies that are differential are shunted by the semiconductor surge protection devices on the far side of the isolation/coupling transformer. Gas discharge tubes can be incorporated on the surge side of the isolation/coupling transformer to shunt extremely high voltages which might breach the isolation/coupling transformer.