Electrical properties of graphite-glass thick-film resistors

Abstract

Purpose The purpose of this paper is to present the properties of thick-film resistors made of novel pastes prepared from glass and graphite. Design/methodology/approach Graphite-based resistors were made of thick-film pastes with different graphite-to-glass mass fraction were prepared and examined. Sheet resistance, temperature coefficient of resistance, impact of humidity and short-term overload were investigated. The properties of the layers fired in atmospheres of air at 550°C and nitrogen at 875°C were compared. Findings Graphite-based resistors with various graphite-to-glass ratios made possible to obtain a wide range of sheet resistance from single O/square to few kO/square. These values were dependent on firing atmosphere, paste composition and the number of screen-printed layers. The samples made of paste with 1:1 graphite-to-glass ratio exhibited the temperature coefficient of resistance of about −1,000 ppm/°C, almost independently on the firing atmosphere and presence of a top coating. The resistors fired in the air after coating with overglaze, exhibited significantly lower sheet resistance, reduced impact of humidity and improved power capabilities. Originality/value In this paper, graphite-based resistors for applications in typical high-temperature cermet thick-film circuits were presented, whereas typical graphite-based resistors were fabricated in polymer thick-film technology. Owing to very low cost of the graphite, the material is suitable for low-power passive circuits, where components are not subjected into high temperature, above the typical temperature of operation of standard electronic components.

Identification of Resistor Types Using Extreme Learning Machine Algorithms and Morphological Operation

“…Resistors function to limit and regulate the amount of electric current that will be used in other components in electronic circuits. Resistors can be made from a variety of component materials and films, even resistance wire (wire made from high resistivity alloys such as nickel-chromium) [3]. In general, resistors consist of several types, including: Fixed Resistor, Variable Resistor, Thermistor, and Light Dependent Resistor (LDR) [4].…”