Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [heat]

Thermal energy; where it comes from, and how to keep it from damaging components

Heat in an electrical system might be caused by resistive losses or inductive heating. It can be dissipated through various forms of heatsink, including passive, forced-air, or liquid cooled.

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My linear voltage regulator is overheating very fast

I'm using a 5 V / 2 A voltage regulator (L78S05) without a heatsink. I'm testing the circuit with a microcontroller (PIC18FXXXX), a few LEDs and a 1 mA piezzo buzzer. The input voltage is aprox. 24 VDC. After running for a minute, the voltage…
m.Alin
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Why don't we make CPUs with 1000s of layers to make use of space in the third dimension?

I am wondering why don't we make processors such as CPUs with 1000s of stacked layers to make use of space in the third dimension now that we have three-dimensional transistors. To be clear I'm referencing making something of a rectangular-prism…
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Why hasn't my LED burned out by now?

I have a 15 year old ReplayTV DVR. I got it used, I'm not sure when, but probably about a decade ago. It's turned on almost all the time, and it has a blue power LED on the front. The LED FAQ says that many LEDs have a rated lifetime of 50,000…
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Why is it dangerous use a coiled extension cord?

What aspect of using a coiled extension cord makes it more dangerous than using an unrolled power cord? Many fire safety websites say that an extension cord should not be used while coiled. Is this due to the cord acting as an air core inductor? I…
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How do I determine the area of copper needed on a PCB to provide adequate heatsinking for a power SMD MOSFET?

I am planning to use the IRFR5305PBF Power MOSFET (http://www.irf.com/product-info/datasheets/data/irfr5305pbf.pdf) to switch on a load. I have determined that I need an external heatsink with Rthsa < 29 C/W. How would I go about determining the…
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Why aren't CPUs cooled from below as well as above?

The transistory bits of an integrated circuit are approximately in the centre of the (plastic or ceramic) package. They sometimes get hot, and we cool them by affixing a heat sink to one side. Sometimes we just blow air over them with a fan. Some…
Paul Uszak
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How to carry high current on PCB

I need to pass high current on some part of my circuit. I used an online PCB track width calculator to see that required track width is about 5mm and minimum clearance is 1mm, which makes it about 7mm width at total just for one track. I need…
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Why exactly do chips start malfunctioning once they overheat?

Once a chip overheats it can start malfunctioning - for example many programs may start failing once some or all parts in a computer overheat. What exactly happens that makes chips malfunction when they overheat?
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Reliability problems with an array of 91 high-power LEDs

I have designed and printed a 4-layer PCB that accommodates 91 infrared LEDs in a 7x13 rectangular layout. This will be used as a backlight for a machine vision project. I am having a problem where individual LEDs are burning out or perhaps becoming…
cxrodgers
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What is killing my MOSFETs?

This is my first post here on electronics stackexchange. I am a hobbyits in electronics, and a professional in programming. I am working on a inductor circuit to heat a workpiece. I have a working setup @12VAC. In short I have the following elements…
Mike de Klerk
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Is a microwave's output power proportional to the mass of its contents?

My friend and I are having a heated debate. On the one hand, he thinks that a microwave oven that is empty, consumes almost no power (not considering lights, lcd, etc). He says that once you put an item in the oven, such as a glass of water, the…
Matthew Goulart
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Is it possible to calculate how much heat dissipation and temperature rise will take place in a resistor

Suppose I have a 100 mAh battery at 20V. I connect a 1000 kohm resistor across it. How much heat will be generated and how can I find the temperature rise in the resistor? As the battery operates I think that the current flow will reduce over time…
quantum231
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Why am I cooking MOSFETs?

I've made a very simple MOSFET LED driver that uses the PWM of an Arduino Nano to switch a MOSFET which controls the power for about 16 meters of LED strip. I am using STP16NF06 MOSFETs. I am controlling RGB LEDs, so I use three MOSFETs one for each…
hamsolo474 - Reinstate Monica
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Using CPU heat to generate electricity

I've been reading Tanenbaum's Structured Computer Organization and he says one of the major bottlenecks for increasing CPU clock speed is heat. So I started thinking: Is it possible to remove the heatsink altogether and use that heat to generate…
Enzo Ferber
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How to 'fix' this in an enclosure without glueing?

I have an enclosure, and want to fix/put a STM32 inside, a relay and probably later a small circuit board. However, the STM (STM32F103C8T6) and the relay do not have holes to fix them... and I do not want to glue them because maybe later I want to…
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