Resistor: Low Heat Capacity, Low TCR, Constant heat dissipation

In summary, the person is looking for a resistor that can quickly generate a constant amount of heat while maintaining a constant resistance and low temperature coefficient of resistance (TCR). They have been using metal film/oxide resistors, but the warm-up time is too long. They are considering using infra red diodes or a hefty lamp filament, but are also open to other ideas. The surface temperature of the resistor will be determined by its power and surface area, and they are looking for a specific type of resistor based on the spectrum of radiation it produces. The Kaye Instruments dry well is suggested as a potential solution.
  • #1
marklv87
2
0
I am looking for a resistor that can dissipate a constant amount of heat at all temperatures immediately.

I have been using some metal film/oxide resistors, but it takes a very long time before the resistor starts radiating heat. I think the material making up the resistor has such a high heat capacity that it takes a very long time for it to completely heat up the material before it starts radiating the ambient air (especially at very low wattage like 1/2W).

Could anyone tell me what the best type of resistor to use for quickly generating a constant amount of heat, but also keeping a constant resistance (low TCR)?
 
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  • #2
The time something takes to heat up depends on its mass and specific heat and temperature differences or the power supplied if it is resistive heating.
Very small resistors with enough power going into them to behave like this would be destroyed in seconds.

If you just want infra red radiation, maybe you could look at infra red diodes?
 
  • #3
Thanks. I actually a constant heat source for the calibration of a calorimeter. Do you have any ideas for something that produces a constant amount of heat and has a known wattage, besides a resistor?
 
  • #4
What about a hefty lamp filament? They can get V hot without frazzling and can handle lots of watts. You'd have to control the voltage to give the appropriate temperature / resistance but that goes for any resistor over such a temperature range.

Why does the warm-up time bother you? You can always use a shutter to keep it away from the experiment until it's hot enough.

The surface temperature will be a function of power and surface area. I think you need to specify what you actually want in terms of the spectrum of the radiation before you can make a proper choice of resistor type and its value.
 
  • #5
Kaye Instruments make calibration and validation equipment which I've used in the pharmaceutical industry. Here is a sweet http://www.kayeinc.com/validationproducts/drywell.htm" which is good for ±0.025°C.
 
Last edited by a moderator:

1. What is a resistor?

A resistor is an electrical component that is used to limit or control the flow of electric current in a circuit. It is designed to have a specific amount of resistance which determines the amount of current that can pass through it.

2. What is meant by low heat capacity in a resistor?

Low heat capacity refers to the ability of a resistor to absorb and dissipate heat. A resistor with low heat capacity will not retain heat for a long time and will not get too hot, making it more efficient and safe to use in electronic circuits.

3. What is TCR in relation to resistors?

TCR stands for Temperature Coefficient of Resistance. It is a measure of how much the resistance of a resistor changes with temperature. A resistor with a low TCR will have a more consistent resistance value, even as temperature changes.

4. What is the importance of constant heat dissipation in a resistor?

Constant heat dissipation is important in a resistor because it helps to maintain a stable temperature, which in turn ensures that the resistance value remains consistent. This is crucial in electronic circuits to prevent malfunction and damage.

5. How do resistors with low heat capacity, low TCR, and constant heat dissipation benefit electronic circuits?

These types of resistors provide more stable and reliable performance in electronic circuits. They help to prevent overheating and maintain consistent resistance values, which is important for the proper functioning of electronic devices. They also have a longer lifespan and are less likely to fail due to temperature changes.

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