The Effect of Overvoltage and Overheating of Resistors

ABSTRACT

BY JEFFREY K. MEUNIER

Ever since the first electrical circuit was invented, its components have been breaking down. The resistor is a common component in an electronic circuit. Do these resistors break down when they are subjected to overvoltage and overheating? If so, at what temperature and voltage do they fail?

When something goes wrong in an electronic circuit, the resistors are the component most likely to short out and fail.

Why study the effect of overvoltage and overheating on resistors? In determining the longevity, reliability and repair record of our TV for example, the resistor play a key role in the circuitry of the TV. The resistors limit the amount of current flowing through the circuits of the television. If for example another component in the TV circuitry breaks down, unknown voltage, and amperage changes will occur and this will put a lot of strain on the resistor, often causing it to overheat. Over time, the resistor will begin to weaken. My project, will determine the effect of overvoltage on the internal temperature and hence failure of different types of resistors.

I will be comparing two types of resistors, the carbon film type, which are found in most electronics, and the metal film type, which are found in power supplies and other high current, high endurance type circuits. The two resistors will be subject to various DC voltages, and using a temperature probe, the exact temperature will be measured. I will record the changes in temperature of the resistor every 30 seconds, and determine the effect of voltage on temperature and the point of failure of the two types of resistors will be compared.