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2007-03-15 00:01:20 · 6 answers · asked by peterphillips.php@btinternet.com 1 in Consumer Electronics Other - Electronics

6 answers

PTC thermistors can be used as current-limiting devices for circuit protection, as replacements for fuses. Current through the device causes a small amount of resistive heating. If the current is large enough to generate more heat than the device can lose to its surroundings, the device heats up, causing its resistance to increase, and therefore causing even more heating. This creates a self-reinforcing effect that drives the resistance upwards, reducing the current and voltage available to the device.
NTC thermistors are used as resistance thermometers in low-temperature measurements of the order of 10 K.
NTC thermistors can be used as inrush-current limiting devices in power supply circuits. They present a higher resistance initially which prevents large currents from flowing at turn-on, and then heat up and become much lower resistance to allow higher current flow during normal operation. These thermistors are usually much larger than measuring type thermistors, and are purpose designed for this application.
Thermistors are also commonly used in modern digital thermostats and to monitor the temperature of battery packs while charging.
These can not be used for application more than 35 K

2007-03-15 00:12:10 · answer #1 · answered by Shemit 6 · 0 0

Thermistor Advantages
Due to wide performance and cost variations among thermistors, generalized advantages and disadvantages may not always apply. Common benefits include:

Low sensor cost: Most thermistors in their basic form cost much less than RTDs. When assembled in protective sheaths the price difference narrows.
High resistance: Base resistance may be several thousand ohms. This provides a larger signal change compared to resistance wire RTDs with the same measuring current, negating leadwire resistance problems.
Interchangeability: Many newer thermistor models are trimmed to very tight tolerances over limited temperature ranges.
Point sensing: Thermistor beads may be pinhead size for point sensing

2007-03-15 00:15:05 · answer #2 · answered by bambola1uk 2 · 0 0

Advantages of thermistors:-
Thermistors generally consist of semiconductor materials. Most thermistors in use nowadays are characterized by a negative temperature coefficient, meaning that their resistance decreases with increasing temperature. Temperature coefficient change can be as high as several percentage factors per degree Celsius. Consequently, thermistors are able to detect even the smallest temperature changes, which would otherwise go undetected with a reverse temperature detectors or thermocouple.

The price to be paid for this high sensitivity is loss of linearity. Thermistor behavior is extremely non-linear and as such, thermistor readings are strongly dependent on process parameters. Consequently, thermistors are not as widely standardized as RTDs or thermocouples.
Disadvantages of thermistors:-
The high resistivity of thermistors is a significant advantage, since it leads to very small errors, which could be even hundreds time smaller compared to measurement errors of RTDs.

In general, thermistors are more fragile than RTDs and thermocouples and therefore require delicate handling and mounting. Another drawback of them is that because they consist of semiconductors, they are more prone to permanent de-calibration (drifting out of their specified tolerance). Contrary to applicability of RTDs and thermocouples, use of thermistors is generally limited to a temperature range of few hundred degrees Celsius.

Small mass of thermistors also makes them very really susceptible to self-heating errors.
https://www.electrikals.com/

2015-08-07 01:14:36 · answer #3 · answered by john 4 · 0 0

Thermistors are small, very stable, are long-lasting, and are usually accurate to within +/- .05% to +/- .02% . This makes them superior to thermocouples and other devices that measure temperature. The disadvantage is that like typical semiconductors, they are non-linear, and so this effect must be compensated for when building circuits. Also, unlike thermocouples, they cannot be used at very high temperatures.



https://www.electrikals.com/

2015-08-06 21:04:26 · answer #4 · answered by shaun 4 · 0 0

1

2017-02-17 13:54:17 · answer #5 · answered by ? 4 · 0 0

do you even know what a thermistor is even for ? with a question like that i would say that you don't

2007-03-15 00:12:02 · answer #6 · answered by Dingy ring 2 · 0 3

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