Tagged Questions

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

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0
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2answers
84 views

Will these heatsinks be sufficient for my mosfets?

I need to control 10 12VDC motors at ~25Amps, so I decided to make my own mosfet H bridges to control it ( with 2 n chan et 2 p chan ). I will need 10 H-Bridge, so 40 Mosfets. ( 20 n chan and 20 p ...
0
votes
2answers
115 views

How can I remove a heatsink that is stuck to a component soldered onto the PCB?

I am modding a wireless router, and one of the problems I have is that it overheats, so it restarts every hour or so I am trying to replace the heatsink. However, I simply cannot get it off. It ...
2
votes
2answers
98 views

Heatsink or IC: how to determine root cause of overtemp?

I have a manufacturing situation where we perform a functional test on a board and we are getting frequent overtemperature failures from a BGA package with a heatsink on it. I would like to be able to ...
0
votes
1answer
100 views

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 ...
1
vote
2answers
77 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 ...
-1
votes
3answers
213 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) = ...
-1
votes
1answer
114 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 ...
2
votes
2answers
616 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. ...
4
votes
4answers
897 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 ...
2
votes
5answers
240 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 ...
4
votes
2answers
208 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 ...
0
votes
2answers
105 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 ...
2
votes
2answers
363 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 ...
1
vote
1answer
355 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 ...
1
vote
1answer
254 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 ...
2
votes
1answer
347 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 ...
1
vote
2answers
419 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 ...
0
votes
2answers
137 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 ...
3
votes
1answer
73 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 ...
1
vote
1answer
136 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 ...
2
votes
2answers
359 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 ...
6
votes
2answers
282 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 ...
3
votes
1answer
398 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) ...
3
votes
1answer
227 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 ...
0
votes
1answer
85 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 ...
2
votes
1answer
172 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 ...
0
votes
2answers
113 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 ...
2
votes
1answer
112 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 ...
1
vote
3answers
478 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 ...
2
votes
3answers
402 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 ...
3
votes
3answers
198 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 ...
3
votes
1answer
193 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 ...
0
votes
2answers
229 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 ...
9
votes
2answers
500 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 ...
4
votes
1answer
322 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 ...
0
votes
1answer
70 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 ...
4
votes
2answers
168 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 ...
3
votes
1answer
324 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 ...
1
vote
3answers
659 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 ...
4
votes
2answers
317 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; ...
0
votes
3answers
519 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 ...
2
votes
2answers
181 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 ...
4
votes
3answers
275 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 ...
3
votes
3answers
2k 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? ...
2
votes
2answers
3k 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 ...
1
vote
2answers
264 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 ...
3
votes
1answer
652 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 ...
4
votes
2answers
394 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 ...
3
votes
1answer
277 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 ...
10
votes
4answers
1k 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 ...