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

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CPU heat-sinks for cooling Transistor?

Can I use CPU heat-sinks for cooling transistors? CPU heat-sinks are low volume and they have been made to cooling a sensitive hot Chip and if the datasheet has said that it requires to hold on the ...
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2answers
52 views

Stray-inductance and capacitance of non-isolated heat-sink

I read an application-note that says the heat-sink (when not electrically isolated), is one of major source of EMI. Well I think this can be corrected at some point by good EMI filters and a good case ...
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3answers
38 views

Calculating the output power of Thermoelectric generator

This question is related with my previous question here I am trying to calculate the output power from a specific TEG, here is it specifications, Open Circuit voltage (Voc) = 5.29V Current (I) = ...
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40 views

MOSFET Heat Sink selection

MOSFET heat sink calculation: I am designing H bridge to drive brushed DC motor . The MOSFET I'm using is IRFB4620PbF. I calculated the MOSFET losses which are 7.8W per MOSFET. I'm not sure if I am ...
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2answers
343 views

Do I need a heatsink for my voltage regulator?

I use L7805CV voltage regulator (TO-220) to get 5 V from a Li-Po 7.4 V 2200 mAh battery. However, after a while, voltage regulator gets really hot. Current measurement showed 200 mA. ...
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4answers
609 views

Why peltier elements have smaller heatsink on cold side?

I have seen in nearly all configurations that Peltier elements are mounted with huge heat sinks on hot side as compared to tiny ones on small side. Is this just a way of explaining the need of heat ...
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6answers
122 views

Heat sink, how much does fin and base width matter?

I have lot of aluminum sheet 0.5mm thickness at home, normally heat sinks that I have seen had 1mm thickness. Now I am wondering should I get that sheet welded as heatsink or do I absolutely have to ...
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191 views

Would a better heat sink be tall or wide?

If we have a heatsink and want to improve it's efficiency would it be better to increase its width or height? What should be the strategy on installing a fan as well? If we increase height and ...
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83 views

Heat Sink for portable refrigerator

I am thinking of making a portable refrigerator with the above schematics, but I am doubtful that the aluminium frame would be enough of a Heat Sink on it's own. All the peltier elements are of ...
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2answers
138 views

How to choose heatsink for power devices (transistor, LED, regulator)?

In many projects I need to choose small, but big enough heatsink for transistor or other power devices (LED, amplifiers, voltage regulators). I know that thermal resistance of many devices is known ...
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1answer
148 views

Attaching a heatsink to a DRV8825 stepper motor driver

I'm using the Pololu DRV8825 Stepper Motor Driver to control a NEMA 17 Steppermotor with an Arduino. The stepper motor requires 1.7A current. According to the driver specs on the Pololu website, if ...
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189 views

Designing a copper plate heat sink

I’m trying to see if a copper sheet I have with me (25 cm X 30 cm, 0.05 cm thick. There's a 6 cm X 6 cm square hole in the center to place a lamp.) is sufficient to keep 36 luxeon rebel LEDs (mounted ...
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162 views

Selecting best Heat Sink for TEG (Thermoelectric generator)

I am trying to solve a puzzle about selecting the right heat sink for my TEG, but I am really confused and lost with lots of equations. Here is the Specification of my TEG (TG12-2.5-01L) Module ...
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2answers
274 views

How does power dissipation for surface mount components work?

I know that with usual through hole components we can attach heatsinks etc. But how does it work with surface mount components? Is having a copper plate around the component the way to go? How do we ...
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2answers
103 views

LED lights and heatsink

I want to make a light for my boat roof. If I were to buy these (or similar), would I need to mount them to a heatsink, or would they be fine just as is? The largest size one has a power output of ...
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70 views

Regime of unsteady flow over heat sink

For my master thesis I'm simulating the cooling of an 2.5D microchip (2 dies next to each other on an interposer (slice of silicium with interconnections)). So I want to calculate the flow over the ...
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1answer
84 views

LM317 TO-220 heat sinking: Junction to case or junction to pad?

I have some LM317 ICs (TO-220) that I'm using on a power supply. I'm trying to figure out the heat sink values necessary to keep the IC under safe operation. All of my requirements are with 700 mA ...
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2answers
221 views

TO-220 voltage regulator, heatsink and mounts

I've received my heatsink and mounts for my voltage regulators. It's the first time for me. I'm not sure about the way to mount the regulator on the heatsink. Mainly a little film, not sure about the ...
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235 views

Pick a heatsink for voltage regulator

I have to dissipate \$2W\$ from a voltage regulator. It's a 7805 in a TO-220 package. The datasheet is here. It's the first time I have to pick those so I would like to have a review of the following ...
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1answer
216 views

Thermal calculation for a D2PAK with a SMT Heatsink

I am trying to calculate the junction temperature of a D2PAK FET that is dissipating 5W. The junction-to-case thermal resistance is 0.4 C/W. The junction-to-ambient (PCB mounted, steady state) ...
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1answer
153 views

Thermal resistance of spring for cheap TO-92 heatsink

I am looking at using a MCP1700 LDO regulator in the TO-92 case style. I was wondering about heat dissipation, and how to make a cheap-o heat sink for it, and had the brilliant idea of using a spring ...
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71 views

Datasheet or termal resistance for this heatsink

Can someone please help me find a datasheet or at least the thermal resistence for the following TO-220 heatsink? My local supplier doesn't have more info about it. They just marked it with those ...
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133 views

Which side should I place a TO-220 transistor on a heat sink?

On TO-220 heat sinks, there are usually two sides, on which the transistor fits easily. One side is more narrow, surrounding the transistor. The other side is more open. Which of these sides is ...
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2answers
109 views

How do I leave electrical connection of heat-sink body?

I usually see that some heat-sinks have thick pins to solder on the PCB, and I'm going to use one of them. Since they are going to be soldered on the PCB, the question rises in my mind about their ...
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100 views

What does “material finish” imply in heat-sink terminology?

I was looking for a heat sink in a long list of products. In heat-sink datasheets, I usually see terms like anodized, no finish or degreased finish. What do these terms mean? What information they ...
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265 views

Peltier Unit Not Working

Recently I ordered a Peltier unit online and received it yesterday. Naturally, I was very excited to play with it. When I first turned it on, One side got hot, an another very cold. I had read that I ...
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3answers
296 views

How efficient are lab bench power supplies? (affected by output voltage?)

As how I understand it, there are two ways of converting DC. One is by using a voltage regulator (zener diode, feedback combination etc), and the other is by using a buck boost converter. Firstly, if ...
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3answers
154 views

What is the electrical connection of heatsink plate of PB case bridge rectifier packages?

I'm going to use two PB-case bridge rectifiers of a certain product in my circuit. I need to know the electrical connection of its heat-sink plate (i.e.; to what pin it is connected to, or if it is ...
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1answer
155 views

Are the non-metallic colored heat sinks of transistor packages electrically isolated/nonconductive?

When I look at transistor packages, I see two different heat sink types. One type is in metallic color, the other type is black plastic colored. I read datasheets of some components, none of them ...
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177 views

Electrically conductive thermal paste

I need a thermally AND electrically conductive heat sink compound for attaching power transistors to an aluminium heat sink. I've given Coollaboratory's LiquidPro a try and that oxidized the ...
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2answers
350 views

How to cool down DIP devices?

I have AD811 in my application that works just fine but as it is working in +/-15 v supply at around 14.5 mA, it's power is around one third of watts. It is hot when touched. I checked if this is a ...
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252 views

How Does One Handle Heat Dissipation in a TO92 Package?

I've experimented with LM7805 analogs from NTE (the NTE960), and the large tab on top makes it obvious how to dissipate generated heat. However, NTE also makes an LM7805 analog in a TO92 package (the ...
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64 views

Choosing proper heat sink for a high power relay

I'm using this Solid-State-Relay to transfer 350 Watt: Input: 45VDC x 10A Output: 10VDC x 10A The following is derived from it's data sheet: Maximum junction temperature 150 C Junction to ...
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2answers
153 views

5V Regulator Power Dissipation

I am using a 5V regulator (LP2950) from ON Semiconductor. I am using this for USB power and I'm feeding in 9V from an adapter. USB requires maximum of 500mA right? So the maximum power dissipation in ...
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1answer
231 views

l7809cv voltage regulator: heat sink or not? [duplicate]

I'm using 9v regulator (l7809cv) with 12 1,5v AA batteries in series so that my application gets both 18v and 9v for my Arduino Uno r3 board. I've been running it for about 15min without any ...
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478 views

Weather proof enclosure for Raspberry Pi

I have built a device based on Raspberry Pi who have to be located on a house's roof. I use an IP67 enclosure with IP69 pressure compensation element with gore-tex membrane. I add silica gel before ...
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2answers
279 views

Can the top off a coke can serve as a heat-sink?

Looking around here for a heat-sink for a TO-18 (2n2222) form I don't quite see one around that will serve. The thought in my mind is whether I may cut the top off the Coke Can, and use it as a sink; ...
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410 views

How can one mount PCB-mounted TO-247 devices to a large plate heatsink?

I want to mount multiple PCB-mounted TO-247 devices to a single large heatsink, something comparable to this: My devices may or may not have mounting holes through them, and their tabs may or may ...
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2answers
176 views

Can motherboard heatsink screws change the inductance of nearby traces?

I have bought motherboard and heat sink. The heat sink uses metal screws and the screw heads are isolated from the board with thin mica insulators. But the screws end up being above some traces on the ...
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3answers
264 views

Heatsink earthing?

I'm currently working on my first circuit that dissipates enough power that I need to use a heatsink. The component in question is a TS1085CZ33 which I'm running with a maximum load of 2.8A ...
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3answers
1k views

What material should I use to insulate my MOSFET from a heatsink?

I have a heat-sink and I want to put two FET's on it. I know I have to insulate it so the metal showing on it doesn't connect and create a path. Is there any good everyday material that would work? ...
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2answers
2k views

Altium Thermal Pad shortcircuit

All my QFN footprints are made with the Altium internal "Tools -> IPC Compliant Footprint Wizard". I get nice footprints with vias in the thermal pad. When I try to place one of those footprints to ...
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2answers
247 views

MOSFET for PWM application

I'm designing an application where a power logic level MOSFET is driven using a 5V PWM signal at 20kHz. The drain current will be approx. 10A and the voltage of the load 12V. I looked into the ...
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1answer
537 views

How to avoid/reduce heat for three 1W LED's?

I'm asking on behalf of a colleague who wanted to make solar powered lighting for poor people. Electricity generated by solar cells are stored in a car-battery sized 12V battery, and that current is ...
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2answers
365 views

Is it bad practice to install an IC to the other side of a heatsink?

Normally, we connect an IC to the other side of a heatsink than shown here: Is it bad to place the IC on the 'unusual' side of the heatsink (and if so, why?) or are both sides each equally ...
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1answer
235 views

Mounting a heat sink on a S202S02 SSR

I'd like to mount a heat sink on a Sharp S202S02 SSR. Here's a drawing the indicates that the back surface of the device might be connected to AC: In the "Design Guide" section of the datasheet it ...
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4answers
949 views

Validate Triac circuit

I'm designing a device to switch a heating device driven by mains power. I've done quite a lot of research and realize there's a lot of information out there but as i'm dealing with potentially deadly ...
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2answers
289 views

Help me understand triac maximum current and when to use a heatsink

Datasheets list , under Absolute Maximum Ratings RMS on-state current = 16 A, for example. 1)How do I know if this is free air maximum current or properly heatsinked? 2)How can two triacs in ...
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3answers
622 views

Can a soapbox-sized device dissipate 10-15W of heat? If yes, how?

Some time ago, I built a soapbox-sized battery testing device. One of its functions was to discharge batteries at a specified current, and it handled most of the common battery sizes well, but its ...
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2answers
114 views

Is Rja in parallel with an external heatsink?

I have done heat sinking before, but now I'm trying to do it on SMT chips which is a bit more difficult. Anyway, I'm wondering whether the resistance between junction and ambient, Rja, is in parallel ...