Hybrid Integrated Surge Protector for Digital Switching System

A newly developed hybrid integrated surge protector (HISP) is described. The HISP circuit configuration employs a three-stage protection circuit. The HISP consists of thick film resistors whose pattern and trimming configuration are designed to enable resistance stability for the surge current to be obtained and newly developed ieadless surge protective devices, such as a three-electrode gas-filled protector, a threeelectrode ZnO varistor, and appliqued fusible resistor. After reliability evaluation testing, the HISP and its component Parts are proved to satisfy system requirements and provisions for practical use. Its Size is one-third and its cost will be one-half of that for a discrete component protector.