Device the resistance to current decreases when temp increases. Im saying resistor cause I know its right but why would thermistor not be right as well?

 

I have no idea what you just asked.

As for thermistor part. It is designed to change the resistance with temperature.
Standard resistors do not change with temperature but only slightly. Sometimes negligible.

 

Some increase and some decrease. Is there a question?

 

Hello,

You might take a look at PTC resistors.

Bertus

 

Nearly all common types of resistor exhibit increasing resistance as temperature increases.

This is the principle behind the correct functioning of a tungsten electric light bulb as a prime example.

So your component is not a resistor.

Do you know any other types of resistive component besides a thermistor (which it may be) ?

http://www.barthelectronics.com/pdf...1 Voltage Coefficient Products_Pulse Page.pdf

 

What is the source of that question?

My initial thoughts were PTC .... but the question as presented lacks clarity.

 

"Some increase and some decrease. Is there a question? "


Carbon resistors have several different forms. One is a mixture of ceramic powder and fine carbon granules held together with a resin type of glue. This has pretty much been discontinued since the advent of modern printed circuit boards where space is at a premium. The type most used these days is a small ceramic base on which a resistive pattern has been deposited. In both cases, the ceramic base is non conducting whereas the carbon forms a current carrying path; the more carbon, the less the resistance.
This type of carbon has a negative thermal coefficient, i.e. the higher the temperature, the lower the resistivity. Its value depends on the details of the form of carbon but often is about -0.0005/°C near room temperature . So if you heat a 1000 Ω resistor by 10 °C then it will have a resistance of 1000 Ω *(1-0.0005*10) = 995 Ω.




https://van.physics.illinois.edu/qa/listing.php?id=18564

 

I have no idea what you just asked.

As for thermistor part. It is designed to change the resistance with temperature.
Standard resistors do not change with temperature but only slightly. Sometimes negligible.

Here is the re-word A device whose resistance to current decreases when its temp increases is called

 

Here is the re-word A device whose resistance to current decreases when its temp increases is called

What kind of "devices" are fair game as an answer? Remember, we have absolutely no clue as to the context associated with this question.

 

Here is the re-word A device whose resistance to current decreases when its temp increases is called

I have absolutely no idea what you are talking about...!

 

A thermistor whose resistance decreases with temperature is called a negative temperature coefficient (NTC) thermistor.

 

That's all true but OP said resistance to current decrease ?

 

You gotta read what the op is trying to say.
He means "resistance to the flow of current"
which is the same as simply saying "resistance".

 

@bwd111: Look up "positive temperature coefficient" and "negative temperature coefficient".

 

Here is an example circuit in conjunction with a VDR used in the older CRT TV's that had a degaussing coil around the tube to automatically switch off the current through the coils.

http://interiorcommunicationselectrician.tpub.com/14120/141200341.htm

Max.

 

I have absolutely no idea what you are talking about...!

That is how the question was written on the board at school word for word and people were answering the question. Guess you had to be there? The correct answer was a resistor

 

That is how the question was written on the board

Too ambiguous!
I guess I would have failed that one.
Max.

 

@bwd111: Look up "positive temperature coefficient" and "negative temperature coefficient".

I did AND that wasn't one of the choices . choices were -rectifier,transistor, resistor ot thermistor

 

I did AND that wasn't one of the choices . choices were -rectifier,transistor, resistor ot thermistor

It would have been really nice to have mentioned this list, particularly after I specifically asked

What kind of "devices" are fair game as an answer? Remember, we have absolutely no clue as to the context associated with this question.

Sheesh.

As several people have been trying to lead you towards, the most reasonable answer (particularly of those given) is thermistor. While all resistors have a temperature coefficient (some positive and some negative), this is not by design by rather a fact of life. A thermistor, on the other hand, is a resistor that is specifically intended to have a large temperature coefficient. Some have positive temperature coefficients and others have negative temperature coefficients.

So neither answer is truly correct for the question as asked, but thermistor is, in my opinion, the better one.

 

I did AND that wasn't one of the choices . choices were -rectifier,transistor, resistor ot thermistor

Arrrgh! Why didn't you say so in the first place.

Resistor is the wrong answer! Tell your teacher I say so.