EEVblog #105 - Electronics Thermal Heatsink Design Tutorial
Why Electrical Engineering Stack Exchange recommends it
Electronics Stack Exchange answerers point people to it when they need to calculate junction temperature and heatsink requirements using thermal resistance.
Recommended by 5 people across 5 different months, 2010 to 2021.
What it is
Dave Jones of EEVblog gives a 31-minute introduction to thermal design for electronics, covering how heatsink calculations work and how to read a heatsink thermal response graph. He also explains emissivity and compares the theory against real temperature measurements.
What people said
Recommends Thomas O · 2010-11 · Electrical Engineering Stack Exchange · on “How to cool ICs?”
Cooling is pretty tricky to get right. In most cases, a heatsink is all that is necessary, however, for higher loads, you will need a fan. Look at a computer power supply. They all use fans, but many will run without them. The heatsinks are usually quite big because the supplies are not very efficient (it turns out it's cheaper to make an inefficient power supply with a big fan than an efficient power supply with a smaller fan.) The fan helps circulate air inside the case, and prevent the other components in the computer from overheating. The first question you need to ask is whether or not the IC you are using can actually dissipate enough power to require a heatsink and/or fan. Many cannot
Recommends Bob · 2015-11 · Electrical Engineering Stack Exchange · on “Is it optimized to design same temperature for several heat sink in a power supply?”
I am making the assumption that by optimal you mean in terms of reliability and longevity. The amount of heat sinks you use does not necessarily matter. In fact, I would argue that the PCB layout should be the ultimate factor in how many heat sinks you use. Heat sinks are a preventative measure. It doesn't really make a difference if you separate each heat sink for each component or if you use a larger heat sink so long as your calculations and testing show that the temperatures stay well within the optimal component operation range. Just off of experience I would say that it would be better to use a larger heat sink for economy reasons provided that the components are near each other on the
Recommends rdtsc · 2016-03 · Electrical Engineering Stack Exchange · on “CPU heat-sinks for cooling Transistor?”
If you want to see how to calculate junction temperature with known devices, see EEVblog #105 - Electronics Thermal Heatsink Design Tutorial [this video] .
Recommends bitshift · 2016-07 · Electrical Engineering Stack Exchange · on “How can I avoid using different batteries to power different components in a circuit board?”
You could use a voltage regulator to create 3.3V from the 14V batteries. Since the device is running from a battery, I would avoid a linear regulator as the power loss would be $$P_{loss} = (14.4V - 3.3V) * I$$ This may be acceptable for your application but I would rather use a switch mode voltage regulator for increased efficiency. When choosing a suitable regulator, you would need to check the datasheet and make sure it can function at a larger temperature than 150 degrees C. This is especially important when using a linear regulator as the power loss is converted directly to heat. How much larger the temperature rating should be, we cannot tell without knowing more details of your applic
Recommends Joren Vaes · 2017-05 · Electrical Engineering Stack Exchange · on “MAX712 charging circuit - diode gets too hot”
The 5 kelvin per watt is from the heatsink itself - the heatsink will become 5 kelvin more above ambient with every watt of power extra being pumped into it. However, inside the transistor, the heat first needs to go from the silicon die to the metal tab on the transistor (this is what we call the junction-to-case thermal resistance). This causes an extra increase in thermal resistance. If you want more information, Dave L. Jones from the EEVBlog has a good video on the topic: [this video]
Cites jippie · 2013-10 · Electrical Engineering Stack Exchange · on “Death of Zen (Audio Amplifier) Questions”
For all of the capacitors, what should the voltage rating be? There are no really big capacitors in the circuit, so don't worry too much about price difference. 35V voltage rating is too low, you don't want your components used at their maximum. I believe the next commonly available voltage is 63V, but I guess you can use anything above 40V. Is the polypropylene required? No the polypropylene is not required. It is probably used because it has better performance for higher frequencies. Electrolytic capacitors have a relatively high parasitic series induction and by connecting a smaller polypropylene cap in parallel you get best of both worlds. The electrolytic capacitor is big and cheap, the
Cites Joaquin Brandan · 2021-03 · Electrical Engineering Stack Exchange · on “Thermal circuit for shared heatsink”
I am following this video from EEV blog where he talks about calculating heatsinks [this video] and I noticed that he does not talk about multiple components sharing a single heatsink. I have lurked around the web but I have not been able to figure out how it is done. This is the thermal circuit for a single transistor in a single heatsink as shown in the video [LINK] How would the thermal circuit for two or three transistors mounted in the same heatsink look like?