With the advent of ruthenium-based resistors, the use of palladium-silver resistors on thick film circuits was all but discontinued until the nineteen eighties, then there was a resurgence due to demand in new niche applications The relatively high power handling of these metallic resistors enables them to be used as secondary lightning surge protection der,ices for telecommunications equipment. For such applications low value compositions, about 0.1 to I Omega/rectangle are printed in a serpentine configuration, typically about 0.5 " x 1 " area to fabricate 10-300 ohm components. These components can withstand multiple mu-second discharges in the thousands of volts. More recently, the resistance range of interest to circuit designers has shifted down to as low as 5.6 ohms. Although if is possible to design 5.6 ohm resistors using the existing 0.1 Omega/rectangle inks, the required area would be large, resulting in bulky circuits. This points to a need for low resistivity inks with move robust power handling capability, while maintaining fight TCR. This paper describes a new series of patented Pd:Ag inks with resistivity as low as .015 Omega/rectangle that address the aforementioned requirements. Extremely high power handling capability of these inks renders them not only useful for lightning surge protection devices, but also for other DC and AC power applications requiring small geometry. In addition, these materials are very useful in current sensing applications because of their tight TCR, coupled with very low resistivity.
