Issuu on Google+

What You Need to Know about Thermistors

Coined from ‘thermal’ and ‘resistor’, thermistors feature a specific type of resistance that is directly proportional to the temperature. When a thermistor is subjected to an abrupt change in body temperature, it is programmed to yield a predictable modification in the electrical resistance. Other types of sensors such as resistance temperature detectors or RTD probe may also be available but a thermistor probe still stands out among the options. The predictable characteristics and unparalleled stability could be cited as two of the major explanations to the superiority of thermistors. 2 Types of Thermistors Thermistors are classified into two categories, namely, positive temperature coefficient or PTC thermistor and negative temperature coefficient or ntc thermistor. For PTC thermistors, a rise in body temperature yields a subsequent increase in electrical resistance. Meanwhile, the dynamics are different for NTC thermistors. When the body temperature shoots up, the electrical resistance drops down. The temperature range that thermistors could operate on largely depends on the manufacturer. Nevertheless, a range of -100 to 600 degrees Fahrenheit seem to be just on the average scale. The discovery of the negative temperature coefficient for silver sulfide by Michael Faraday in 1833 has been regarded as a major milestone in thermistor technology. Since then, innovations and developments to upgrade the development of thermistors have been rolling fast. The effectiveness and quality of any thermistor are based on its temperature coefficient of resistance. The higher the coefficient is, the higher is the quality of this particular thermistor. Fortunately, modern technology has paved the way for this feat to be achieved easier and faster. The change in body temperature could also be attributed to different causes or factors. Conduction or radiation from the external environment could trigger an alteration in the temperature. Likewise, the change could also be brought about by ‘self-heating’ triggered by dissolution of power. In a nutshell, the change could be triggered by either internal or external factors. The applications and uses of thermistors are dictated by the specific type they belong to – whether they are PTC or NTC. For PTC thermistors, they could serve

as better replacement for fuses. Their current-limiting characteristics pave the way for these thermistors to be useful and valuable for circuit protection. Another area wherein PTC thermistors could be well integrated into is in CRT displays. Most CRT displays feature a degaussing coil circuit. Numerous individuals and entities have already started using thermistors as timers for these coil circuits. Degaussing circuits with PTC thermistors have been noted to be less costly but more reliable. NTC thermistor also yield promising applications. For automotive applications, they could be effective coolant and oil temperature monitors. Power supply circuits have also been integrated with NTC thermistors to function as inrush-current limiting devices. In fact, specific NTC thermistors have been developed for these specific uses. Even the food and handling industry could reap the benefits of NTC thermistors. Indeed, investing in thermistors could be a wise decision. There may already a lot of players in thermistor technology but you need to make sure you will be working with a reputable manufacturer. You can never go wrong by ink 19ing a deal with an ISO-certified company. For more details, please visit our site:

What you need to know about thermistors1