There's a nice little hand-held battery operated IR temperature meter
at Radio Shack for a few bucks. F or C, works great, bought several.
that reference is over 18months old.
They have probably replaced that with a newer super duper model 6times over, that is if the manufacturer is still in business.
A very interresting thread this..
I'm just in the process of completing an amplifier project using Crescendo ME cards, and during assembly and testing, I've used a hand-held infrared thermometer to check for temperatures.
Since my heatsinks are in natural aluminum finish, the thermometer doesn't measure the right surface temperarure on these. It is typical for these thermometers to give a lower than actual reading on shiny/ bright surfaces, so bear this in mind, or you might underestimate temperatures from erroneous measurements!
I did use my IR thermometer on the black bodies of the output transistors, and that I found very usefull.
As I didn't use a over-dimensioned heat-sink, on the contrary, it's probably on the small side, I couldn't take it for granted that thermal dissipation would be a non-issue.
So far, I've found that when idle, the device package reaches about 50-55 deg. C.
This may sound like a bit much, but the mosfet's in my amp run at a relatively high idle current of about 200mA.
Running the amp at "normal" listening levels, the temperature only rises to about 60 deg C on the device. Nice and warm, but not frighteningly so.
This is all with the lid off, but I've fitted a couple of fans, more to aid air circulation than for full out forced cooling.
The fans are temperature controlled.
If I stick the fan temperature sensor straight on the heatsink, they go up to full speed which is audible on silent parts during normal listening.
The plan is to experiment with the positioning of the thermal sensor to get a good balance between fan-speed and acceptable operating temperature.
Hopefully, it is possible to reach a balance where the fans will run at a low speed during normal listening and only spinn up to full capacity under heavy amplifier load.
These IR thermometers have come down to a very affordable price, so If you do some amplifier-building, the investment should be justifiable.
Not to mention all the other stuff you will find your self using it for, great in the kitchen, great for checking pan-temperature when frying steak, or keeping controll on the temperature when you do a bernaise sauce so it doesn't get too hot and fall appart!
Allso great for checking the temperature of your wine before serving..
Finally, regarding putting heatsink on "non-power" components, remember that a heatsink can sink heat both ways!
I'm just in the process of completing an amplifier project using Crescendo ME cards, and during assembly and testing, I've used a hand-held infrared thermometer to check for temperatures.
Since my heatsinks are in natural aluminum finish, the thermometer doesn't measure the right surface temperarure on these. It is typical for these thermometers to give a lower than actual reading on shiny/ bright surfaces, so bear this in mind, or you might underestimate temperatures from erroneous measurements!
I did use my IR thermometer on the black bodies of the output transistors, and that I found very usefull.
As I didn't use a over-dimensioned heat-sink, on the contrary, it's probably on the small side, I couldn't take it for granted that thermal dissipation would be a non-issue.
So far, I've found that when idle, the device package reaches about 50-55 deg. C.
This may sound like a bit much, but the mosfet's in my amp run at a relatively high idle current of about 200mA.
Running the amp at "normal" listening levels, the temperature only rises to about 60 deg C on the device. Nice and warm, but not frighteningly so.
This is all with the lid off, but I've fitted a couple of fans, more to aid air circulation than for full out forced cooling.
The fans are temperature controlled.
If I stick the fan temperature sensor straight on the heatsink, they go up to full speed which is audible on silent parts during normal listening.
The plan is to experiment with the positioning of the thermal sensor to get a good balance between fan-speed and acceptable operating temperature.
Hopefully, it is possible to reach a balance where the fans will run at a low speed during normal listening and only spinn up to full capacity under heavy amplifier load.
These IR thermometers have come down to a very affordable price, so If you do some amplifier-building, the investment should be justifiable.
Not to mention all the other stuff you will find your self using it for, great in the kitchen, great for checking pan-temperature when frying steak, or keeping controll on the temperature when you do a bernaise sauce so it doesn't get too hot and fall appart!
Allso great for checking the temperature of your wine before serving..
Finally, regarding putting heatsink on "non-power" components, remember that a heatsink can sink heat both ways!
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When using an IR temperature device, be that a camera or just a plain IR thermometer, you have to take the emission correction factor into account.
If you put in a bit of effort to do so, you can get reasonable results with an IR thermometer. It does however take that you read the manual, and understand how it works, to get anything useful out of it.
A while ago I bought myself one of those Fluke thermal imagers.
As mentioned earlier in this thread, such a device sure makes things possible, that we could not even dream of being able to do without.
Partly it works wonders when building amps, but just as important is is pretty much a miracle tool for finding broken/dying components in a circuit.
Thermal imaging equipment also have many other purposes, like finding moisture in a building, or checking the isolation of the house.
Lately I have even used it on the car, as the coolant system was acting up.
I think as the thermal imaging cameras gets cheaper, we will see them become quite popular, it's a wonderful tool.
Btw., Fluke sells a reasonably good IR thermometer at the moment for less than 100$, that is well worth the money.
Magura
EDIT: Added an image of an amp I made a while ago. It shows how small temperature differences a camera can measure. Note that the entire amp is within less than 1C, but the variations are obvious.
If you put in a bit of effort to do so, you can get reasonable results with an IR thermometer. It does however take that you read the manual, and understand how it works, to get anything useful out of it.
A while ago I bought myself one of those Fluke thermal imagers.
As mentioned earlier in this thread, such a device sure makes things possible, that we could not even dream of being able to do without.
Partly it works wonders when building amps, but just as important is is pretty much a miracle tool for finding broken/dying components in a circuit.
Thermal imaging equipment also have many other purposes, like finding moisture in a building, or checking the isolation of the house.
Lately I have even used it on the car, as the coolant system was acting up.
I think as the thermal imaging cameras gets cheaper, we will see them become quite popular, it's a wonderful tool.
Btw., Fluke sells a reasonably good IR thermometer at the moment for less than 100$, that is well worth the money.
Magura
EDIT: Added an image of an amp I made a while ago. It shows how small temperature differences a camera can measure. Note that the entire amp is within less than 1C, but the variations are obvious.
Attachments
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I don't think so - 18 months are not 18 years. One of this models this could be:
1) RadioShack® IR Thermometer, Catalog #: 22-170, Model: TN439L1
RadioShack IR Thermometer : Health & wellness | RadioShack.com
RadioShack® IR Thermometer in Sacramento | sacbee.com
2) ThermoHAWK™ Infrared Non-Contact Model: Q3I-TH220 Catalog #: 55039404
ThermoHAWK Q3I-TH220 Infrared Non-Contact Thermometer : Testers | RadioShack.com
3) ThermoHAWK™ TH420 Infrared Non-Contact Model: Q3I-TH420 Catalog #: 55039405
ThermoHAWK TH420 Infrared Non-Contact Thermometer : Testers | RadioShack.com
very cheap about amazon:
http://www.amazon.com/Thermohawk-Q3I-TH220-220-Non-Contact-Thermometer/dp/B001GQLGAU
and also there:
http://www.q3i.com/thermohawk_series.php
in Germany the brand name Fluke is good available but a bit more expensive:
http://de.rs-online.com/web/5075346.html
http://www.messtec24.com/product_info.php?info=p546_Fluke-62-Mini-Infrarot-Thermometer.html
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Fluke - FLUKE-62 - Meters - Test & Measurement - Allied Electronics
These are quite reliable and fairly cheap.
Magura
These are quite reliable and fairly cheap.
Magura
board mounted heat sinks are often rated for "thermal resistance in natural convection with 75 C rise"
- they have to get hot to cause enough convection to make their heat transfer #
working backwards from typical 150 C max Tj of transistors you have to use <50 C delta across the total heat sink + mounting + packaging thermal resistance to work in a 25 C ambient if your'e really trying to dump the nominal W rating of the heatsink
add in case internal temp rise (added 25 C is a better target) and you can see that massive derating of the heat sink is needed
- they have to get hot to cause enough convection to make their heat transfer #
working backwards from typical 150 C max Tj of transistors you have to use <50 C delta across the total heat sink + mounting + packaging thermal resistance to work in a 25 C ambient if your'e really trying to dump the nominal W rating of the heatsink
add in case internal temp rise (added 25 C is a better target) and you can see that massive derating of the heat sink is needed
I am not sure what you mean by "non power" but I think you are confused.
A device that has a voltage drop across it when a current flows will heat up from it's "off" state.
Any device that heats up will dissipate that power while it rises above ambient temp to reach it's operational temperature.
Any device that dissipates power will be hotter than ambient temperature.
It does not matter whether a sink is attached or not, a device that dissipates power will always be hotter than ambient in it's stable state.
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