06-12-2020, 05:57 PM
Russ
about that help with heat dissipation...larger size will and will not help with the heat dissipation.
Depends what you mean by the help.
If you mean that the new resistor inside the mold itself would handle the heat better....yes, simply because it is designed for it.
But here is some physics for you:
- The resistor is, well, encapsulated. This means the intended heat exchange with the ambient air is greatly impeded now. However if used well under the specifications it is still OK for it as it simply will not produce enough heat to self-destruct, even with no now air cooling.
- If used not well below specs. It will heat up way more than it would otherwise. So de-rate your resistor some 50%.
- Now let's talk the outside overmold. If it is ceramics-based, it will not suffer from the heat. I it is plastic, especially painted, it might, depending on how much heat the internal resistor produces.
The worst part is, this is exactly where your resistor power rating practically does not matter. Why? Because you produce the same amount of heat independently of the wattage rating, and it all is trapped inside that piece of painted plastic. Better yet, whatever resistor you used, you said you are trying to make it the same size to look authentic, so if you dissipate 1/4W, either your 1/2W or 1W resistors will make the same amount of heat over the same time trapped inside the same exact size plastic tube.
This is not to say that this technology is deeply flawed, not necessarily, and Steves or yours eresistors are just fine....as long as we are dealing with low dissipations. Try to make real old 3W dogbone this way and dissipate 1W.....you will feel the smell.
about that help with heat dissipation...larger size will and will not help with the heat dissipation.
Depends what you mean by the help.
If you mean that the new resistor inside the mold itself would handle the heat better....yes, simply because it is designed for it.
But here is some physics for you:
- The resistor is, well, encapsulated. This means the intended heat exchange with the ambient air is greatly impeded now. However if used well under the specifications it is still OK for it as it simply will not produce enough heat to self-destruct, even with no now air cooling.
- If used not well below specs. It will heat up way more than it would otherwise. So de-rate your resistor some 50%.
- Now let's talk the outside overmold. If it is ceramics-based, it will not suffer from the heat. I it is plastic, especially painted, it might, depending on how much heat the internal resistor produces.
The worst part is, this is exactly where your resistor power rating practically does not matter. Why? Because you produce the same amount of heat independently of the wattage rating, and it all is trapped inside that piece of painted plastic. Better yet, whatever resistor you used, you said you are trying to make it the same size to look authentic, so if you dissipate 1/4W, either your 1/2W or 1W resistors will make the same amount of heat over the same time trapped inside the same exact size plastic tube.
This is not to say that this technology is deeply flawed, not necessarily, and Steves or yours eresistors are just fine....as long as we are dealing with low dissipations. Try to make real old 3W dogbone this way and dissipate 1W.....you will feel the smell.
