Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [ptc]

Many components have a positive temperature coefficient (PTC). (Questions about polyfuses should be tagged [polyfuse] instead).

Many components have a positive temperature coefficient (PTC).

A positive temperature coefficient is most commonly discussed in relation to:

  • thermistors, thermocouples, and similar devices used to measure temperature. Questions about these devices should be tagged with or .
  • PTC resettable fuses (Some people generically call every device in this category a "polyswitch" or "polyfuse", even devices that don't come from the manufacturer that trademarked those names). Questions about PTC resettable fuses should be tagged with instead of the "ptc" tag. See also .
  • The positive temperature coefficient of the incandescent light bulb used to stabilize the Wien bridge oscillator in L. Meacham and William Hewlett's extremely stable and low distortion (for 1939) oscillators.

Should the tag "ptc" be a synonym for polyfuse (like "pptc")?

48 questions
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Polyfuse (resettable PTC) lifetime

There is a proposed design that could have a polyfuse tripping many times. Is there any lifetime to these things? Number of resets? I looked here but could find no such spec. I'm a little worried by the design... but perhaps needlessly. I'll send…
George Herold
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Can silicon temperature sensor (e.g. KTY84)'s polarity be inferred if it's inaccesible - polarity band cannot be visually checked?

I have two electric motors at my disposal, both equipped with KTY84-130 silicon temperature sensors (PTC thermistors). The sensors themselves are buried deep within the innards of the motors and I don't want to meddle there if not absolutely…
anrieff
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Hot Glue Gun NTC Heating Element?

I decided to take apart a cheap hot glue gun to see how easy it would be to replace the heating element to power it from battery instead of mains. I found the crystal heating element sandwiched between 2 metal plates, kept in compression against the…
Justin
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PTC fuse failure mode?

PTC fuses are resettable, i.e. they go to high resistance when tripped and return to low resistance when they cool. Some examples would be e.g. Bel fuse 0ZCJ or Littelfuse Polyfuse series. One thing the manufacturers are coy about is what is the…
Barleyman
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Voltage detection / Universal uC Input => CLD, PTC

I'm currently developing a open-source "Home-PLC" for home automation. Every thing runs fine so far and I have a module with fixed voltage AC inputs and outputs. In the next step I want the build 'universal inputs' (power detection @ AC/DC…
Joerg
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Thermistor with sharp "cutoff" edge (reaching around 45°C)?

Is there a thermistor which has a very low resistance up to about 45°C and then, within a few degrees, raises the resistance to a very high resistance? Sort of like a self resetting thermal cutoff fuse, but with a raising resistance before cutoff.
Christian
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Mains Filter for Power Line Comunication

I have two questions about Mains filters and their impedance effect on PLC. 1) With respect to signal propagation relative to the Line impedance: As the signal is sent, via the power line, it will take the path of least resistance. Therefore the…
Gareth T.
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12 V 20000 mAh Li-ion battery pack gets very hot

I'm trying to power a heated lunch box I got from Amazon (this one) via this - 12 V 20000 mAh Li-ion battery pack, which appears to be 6x 18650s. When I plug it in, the battery heats up significantly, though it's enough to heat up my food, I'm…
YanO
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Component Identification - NTC? PTC? ϑ? [BMW Z4 E85 Heated Seats]

I'm trying to identify a part in a circuit that has next to zero information out there on the web other than the wiring diagram itself direct from BMW's NEWTIS. I'm trying to fathom out what the circled component is. I think it's a PTC, with the…
IAmOrion
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Does a PTC fuse blow out and fail?

Can a PTC fuse blow out and malfunction after it resets? The attached image shows a PTC that seems to have blown out. How do you determine if it needs to be replaced or not?
Boon
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What is the possible reason that cause the failure (burnt) of PTC in an electronic ballast?

What is the possible reason that might cause the failure (burnt) of PTC in an electronic ballast? I have been using this VOSSLOH SCHWABE brand electronic ballast and recently it has been burning up after several years of usage. When I investigate…
Chris Aung
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Driving / controlling PTC heating element

I have a 24V / 80W desoldering gun which turned out to have a PTC heating element. I'm not sure why they chose that, as it is intended to be temperature controlled. The resistance of the heating element is about 1.6Ω at room temperature and…
Julian F. Weinert
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Do eFuses work with AC current?

I was wondering if integrated eFuse solutions exist that are designed to protect a low voltage AC bus. In my application I would like to replace a 2A PTC that protects a 24VAC bus but I cannot find an IC which explicitly states that it supports AC…
Giorgio
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PTC thermistor vs. NTC thermistor for measuring the temperature of a liquid

I have to measure the temperature of a liquid. Does a PTC thermistor has any advantage over an NTC one? I mean, are there conditions where one is preferred over the other?
Manzillo
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How to protect a motor from overheating using a PTC Thermistor

I want to design a circuit to protect against overheating of motor windings by using a PTC Thermistor. As I simulated it in Proteus, the following questions came up; Thermal Contact Res. (°C/W) Thermal Res. to Ambient (°C/W) Time constant…
Omar Furkan
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