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Questions tagged [heatsink]

A heatsink dissipates heat into the surrounding air and thus provides cooling.

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73 views

Heatsink pad connected to ground pins

Is it safe to use the exposed heatsink pad of a QFN to also connect the ground pins of the IC? (Like this question, but in my case the pad has many vias connecting it to ground plane.) Additionally, ...
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1answer
43 views

Electrical insulation resistance of TO-220 package with SIL pad and plastic shoulder washer?

What would a ballpark insulation voltage (HI-POT) rating be for a TO-220 package (with a "hot" tab) mounted to a grounded heat-sink with SIL pad and shoulder washer? I am not seeing much ...
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2answers
44 views

How do I determine the junction-to-ambient thermal resistance?

For a project I'm working on, I was considering using an AS7805 to supply low-noise 5V power to some sensors. (due to the uncertainty that resulted in asking this question, I've since changed to a ...
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8answers
7k views

Why are electrically insulating heatsinks so rare? Is it just cost?

Edit: It seems my initial question (Why are there no insulating heatsinks?) was based on a false premise, and there are in fact insulating heatsinks--I just wasn't able to find them with a cursory ...
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46 views

Tesla coil circuit troubleshooting

Ok so we are making a tesla coil. Here is the circuit diagram we are referring: Now it worked when we first made this. The light bulb lights bulb when we bring it near to secondary coil. Then we ...
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3answers
56 views

Mounting finned flat-base heat-sink with no tabs or screw-holes

The heat sink has a flat base with no tabs or holes. How is it supposed to be mounted on a PCB? Wire brackets soldered to the PCB come to mind but then how does one ensure there's enough pressure ...
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1answer
52 views

LED ULN2803 thermal / heatsink questions

I'm intending to use LEDs of 5mm, which have a max forward current rate at 30 mA, or a value of 100 mA, with 10% 1 kHz duty cycle, in a circuit like the one below except some changes: STM32F103C8T6 ...
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1answer
57 views

Transistor Inverter - when does excessive small wattage become a problem?

I'm trying to choose the best values of resistors given the stock I have so that I can deliver sufficient power and current to an HM-TRP radio module. In this circuit, I used the 100K resistor ...
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1answer
55 views

How can I install mini aluminium heatsink to wireless card?

I am thinking about increasing txpower of the my wireless card. But I am worrying about the heat can damage my wireless card. My solution is installing aliminium heatsinks on the wireless card. My ...
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2answers
101 views

install heatsink on BJT

I am facing the problem with the heat of transistor disturb sensor reading. Here the link refer problem I am using BC548 transistor. It is a bit hot when operating because it disipates power around ...
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4answers
99 views

MOSFET thermal resistance

I am trying to calculate the total thermal resistance of my FET to see what heat sinks are required, are the following calculations correct? $$ Power = \frac{T_{jmax} - T_a}{\theta_{JC} + \theta_{CA}}...
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158 views

I want to attach a heat sink to the inductors on my motherboard, which glue could I use? [closed]

If I wanted to attach a heat sink to the inductors on my motherboard, which glue could I use? I have a Gigabyte A320M-S2H, this motherboard has heating problem when used with the AMD ZRyzen 7 2700X ...
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246 views

Can i get away with a pcb heatsink for a triac?

so, i have a bunch of to-220 L4006L5TP triacs laying around and i have to design an AC phase control pcb, reading the datasheet i saw that the Rθ(J-A) is 50°C/W, the Rθ(J-C) is 3.3°C/W and the voltage ...
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2answers
119 views

Confusion with relating thermal resistance temperature, and electrical power and heat sinking

What is meant by the following?: In general, a device with a thermal resistance θ equal to 100°C/W will exhibit a temperature differential of 100°C for a power dissipation of 1 W, as measured ...
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1answer
55 views

Interpreting a datasheet of resistor for heat sink

I will have this 47k 50W wire wound resistor which will be across line and neutral which means 230 VAC rms. So the electrical power in theory will be V^2/R = 1.2 Watt. How should one interpret this ...
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4answers
163 views

1N5822 schottky diode heatsinking

Is the cathode for schottky diode hotter than the anode, as is common for most diodes, or is it reverse polarity? A schottky is a metal-semiconductor junction, with the metal at the anode. So it ...
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2answers
81 views

Intermittent power dissipation calculation on TO-220 package

For a certain application I will be using this resistor. I might also go for this other resistor if needed. The working conditions are: Ambient temperature (max): 70 ºC Power to be dissipated: 15 W "...
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2answers
117 views

MOSFET's getting too much heat up without any load

I am working on inverter, MOSFETs in h-bridge inverter goes heat up without any load attached. I also attached pull-up and pull-down resistor on it. here is my circuit duagram. EDIT Sources of PMOS ...
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3answers
448 views

How to calculate Junction to Ambient temperature of LED?

I'm trying to calculate the Junction to Ambient temperature for this Cree LED: https://www.mouser.ca/datasheet/2/90/ds--XHP502-1093532.pdf I know how to calculate this: Junction Temp = Junction to ...
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3answers
422 views

The best way to attach a heatsink to a SMD component?

There's a SoC I want to throw a heatsink on. What's the best way to do this for maximum heat transfer and longevity? I know of thermal pads, thermal adhesive, and thermal paste -- but when it comes ...
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2answers
161 views

Voltage regulator with heatsink gets overheated

First of, I'm sorry if I'm using the wrong terms or if I'm pointing out something that is obvious to most, this is not my profession, it's only a hobby. I have an input voltage of 12V 5A which is ...
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2answers
78 views

Synchronizing IC Temperatures

I have several separate identical PCBs with identical ICs on them. It's fairly critical for this application that all the IC's are synchronized in regards to temperature. E.g. if one increases by 1 ...
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3answers
329 views

Electrically Grounding a Large Heatsink to PCB Layer Ground

I have a 100x100mm board that is directly attached to a same sized heatsink on one side (touching heat producing IC packages). The board is 4 layer, with a large ground middle layer. Is there any ...
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2answers
232 views

Thermal pad thickness

We are going to use GAP PAD HC 5.0 thermal pad to transfer the heat from a FPGA (XCKU040) to a heatsink. My question is regarding the thickness I should choose to obtain best performance. On the one ...
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0answers
76 views

What fan could I use to extract hot air from an oven?

I am making an reflow oven. I've decided to use the picoReflow to do the job and monitor it. The oven is originally a lab oven, and it doesn't cool quickly at all. It has a vent at the top which I'd ...
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1answer
261 views

Galvanic Corrosion of Copper, Aluminum, and ENIG Plating

I need to attach a heat sink to a PCB. The PCB is a 560 mm x 9 mm strip of LEDs. The LEDs vary from mid-power to high power. I have a pure copper solution for the high power. I am investigating the ...
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1answer
1k views

Air cooled heatsinks - horizontal or vertical fins?

If we have a heat sink with fins, for example like this how does the efficiency vary between horizontal and with the fins vertical in non forced air?
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1answer
61 views

Selecting power resistor

I want to build a thermostat and I'm not sure what power resistor to choose. The thermostat will be build inside a broken microwave oven. The resistors will be connected to 230V AC and they will be ...
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0answers
32 views

Techniques for probing circuits that would normaly be covered by a heatsink

I have a circuit board I have to probe and measure to first debug and then later on verify performance. The circuit board contains a power amplifier that requires a heatsink in order to keep the ...
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3answers
174 views

LT3083 heat dissipation

I was looking through a datasheet for the LT3083 regulator and in the typical applications sections this caught my eye: Provided input/output ratings could easily lead to over 20W being dissipated on ...
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5answers
4k views

Why are DIMMs not equipped with a heat sink like a CPU?

I know that a DIMM is composed of a set of chips that contain control logic managing the decode and prefetching memory operations. According to a product specification, I found that newer RAM works at ...
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2answers
320 views

Transistor Power Dissipation / Overheating

I am working on an audio project in which a voltage controlled square wave oscillator drives a 5W 4Ohm Speaker. I am using a unipolar 12V supply. In order to limit the current going through the ...
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6answers
3k views

Would this component require a heat sink?

Would this LM7805 voltage regulator require a heat sink? It will regulate 12V to 5V and will be used for a 5V sensor which draws 4mA current.
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2answers
192 views

Thermal Management for Arcol HS50/HS100 50/100W Wirewound resistors

I'm designing a 100W dummy load for a guitar amplifier using Arcol HS50 and HS100 resistors. Here's a link to the datasheet: http://www.arcolresistors.com/wp-content/uploads/2014/03/HS-Datasheet.pdf ...
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1answer
78 views

Heat dissipation on high power resistor

A resistor (~1 cm x 1 cm x 4 cm) with I = 5 A and V = 10 V (P = 50 W) is perfectly attached (on the 1 cm x 4 cm side) to a flat copper piece with known thickness, D = 5 mm (no fins). Ambient T is 20°C....
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4answers
301 views

Is it possible to use a heatsink without a peltier plate?

At the moment I am working on a project which implies LEDs for street lighting. I need to dissipate around 24 W of heat. In order to do so, I calculated how much heat is dissipated into the air, and ...
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1answer
28 views

Built in Tablet Chargers in the Van--Voltage regulation heat dissipation a problem?

Ok, for fun and enjoyment I have decided to build in chargers in a number of positions on the "Mom Van." But either I can't do math, or I am missing something. I want tablet style chargers capable ...
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2answers
155 views

Can a heatsink protect a PYNQ-Z1 board from damage? If so, which one should I use?

I'm going to purchase a PYNQ-Z1 FPGA development board from Digilent (Link: https://store.digilentinc.com/pynq-z1-python-productivity-for-zynq/). However, some of the comments on the linked page say ...
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2answers
199 views

Can you solder the tab on a FQP30N06 MOSFET to the GND plane on a PCB? [closed]

I've got a FET that I want to be laid down on my first PCB. Can I solder the tab to a pad attached to the GND plane as someone on reddit suggested?
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3answers
251 views

Heat sink on the bottom or on the side?

I am considering a thermal design and due to space requirements I was considering different orientation of the heat sink, namely putting it bottom down, obviously, and puttin it on the side as in ...
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1answer
84 views

Can silicone be used in a led bulb to transfer heat from a led filament (COB) to the glass?

I am building my own led filament bulbs, and would like to use silicone to secure a flexible filament in place inside a glass test tube. Assuming that the tube is filled with silicone, would silicone ...
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1answer
326 views

Modding Copper Heatsink - Fans for Better Heat Dissipation

I have been working on a little project of mine in which I try cool a small peltier using this laptop heat sink fan. The peltier I am using is rated 10W, while the laptop fan is rated for 18W of ...
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3answers
510 views

Transistor heating up problem

I have an LM317AHVT power supply with PNP pass transistor. I noticed that the power transistor is heating up to about 64C after a few minutes. I am using an 130x80x30mm heatsink and an 92mm fan to ...
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1answer
166 views

Expand heatsink contact area with larger copper plate? [closed]

I'm looking at DIY projects where a COB LED is cooled by an all-in-one CPU liquid cooler, however the contact area in a CPU heatsink will only fit one high-power LED. I'm considering how I could use ...
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2answers
208 views

Heat sink design

I'd like to implement some kind of heat sink to cool down the following step-down power converter: https://www.pololu.com/product/2851, but I have zero experience with heat sink techniques. The ...
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2answers
83 views

Experimental mounting for high power LED

I have bought this UV LED for experimental purposes. I do not want to go to the expense of creating a miniature PCB to mount it, but I obviously need to heatsink it. It is tiny - 3.3mm x 3.3mm and can ...
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3answers
779 views

What heat sink should I use for this 50W resistor?

I want to run 80 Watts of power through 2 50W 1Ohm resistors: http://www.upe-inc.com/upe-ate-resistors/wirewound-aluminum-housed-axial-resistor/ It's the RB50 series. When trying to calculate what ...
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2answers
1k views

Heatsink calculations for a TRIAC

It's very rare that I get to design applications in need of cooling so I haven't had the need to study in-depth about that, but now I face an occation where I need cooling for a TO220 and I'm unsure ...
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2answers
103 views

Three phase rectifier heatsink

I need to choose a heatsink and a fan for cooling a three phase rectifier. Let's say that the total power dissipation is 1.8kW and that the rectifier is made of three half bridge IGBT/diode modules ...
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1answer
228 views

Help in Thermal PAD and glue calculation (equivalence) in shared heatsink

Hello if I have 15 chips to dissipate 1W each (thus 15W in total), by math calculation, which of the next three possibilities is better: 1) using a unique shared heatsink @1.7K/W with 0.5mm thermal ...