What is a thermistor thermometer?
What is a thermistor thermometer?
A thermistor is a resistance thermometer, or a resistor whose resistance is dependent on temperature. The term is a combination of “thermal” and “resistor”. It is made of metallic oxides, pressed into a bead, disk, or cylindrical shape and then encapsulated with an impermeable material such as epoxy or glass.
What is a thermistor used for?
Thermistors, derived from the term thermaIly sensitive resistors, are a very accurate and cost- effective sensor for measuring temperature. Available in 2 types, NTC (negative temperature coefficient) and PTC (positive temperature coefficient), it is the NTC thermistor that is commonly used to measure temperature.
How do you identify a thermistor?
Identifying thermistors and RTDs To determine whether the sensor is a thermistor or RTD, as well as the type, you must measure the resistance between the two different-coloured wires: An RTD PT100 will have a resistance of 100 ohms at 0 °C. An RTD PT1000 will have a resistance of 1,000 ohms at 0 °C.
Why resistance of thermistor decreases with increase in temperature?
Depending on materials used, thermistors are classified into two types: With NTC thermistors, resistance decreases as temperature rises; usually due to an increase in conduction electrons bumped up by thermal agitation from the valence band.
Where is the thermistor located?
Remove the thermistor cover Locate the thermistor in the refrigerator section; it’s under a small plastic cover attached to the surface of the back wall, side wall or ceiling.
Which type of thermistor is chosen for temperature measurement and control?
The relatively large negative response of an NTC thermistor means that even small changes in temperature can cause significant changes in their electrical resistance. This makes them ideal for accurate temperature measurement and control.
How is a thermistor affected by temperature?
The thermistor Their resistance decreases as the temperature increases. At low temperatures, the resistance of a thermistor is high, and little current can flow through them. At high temperatures, the resistance of a thermistor is low, and more current can flow through them.
Is thermistor is directly proportional to temperature?
Hence the value of resistance decreases as temperature increases and the value of resistance decreases if its temperature increases. A thermistor is a special case of a semiconductor having a large negative temperature coefficient of resistance. Thermistors are also called as temperature-sensitive resistance.
How is thermistor used in a thermostat?
RTI also explains how a thermistor is used to provide temperature control, such as provided by a room thermostat. By placing a thermistor in series with a relay coil and potentiometer…, a simple temperature controller is obtained. The potentiometer will control the switching temperature.
What is a thermistor and how does it work?
NTC Thermistors. An NTC thermistor is a thermally sensitive resistor whose resistance exhibits a large,precise and predictable decrease in resistance,as the core temperature of the element increases over
What is thermistor used for?
A thermistor is a resistor, or type of sensor used to regulate and measure temperature, such as heat and cold. A thermistor is made up of ceramic with a high precision at a specific temperature level.
What does a thermistor do in a circuit?
Thermistor. An NTC is commonly used as a temperature sensor, or in series with a circuit as an inrush current limiter. With PTC thermistors, resistance increases as temperature rises. PTC thermistors are commonly installed in series with a circuit, and used to protect against overcurrent conditions, as resettable fuses.