Questions tagged [heatsink]
A heatsink dissipates heat into the surrounding air and thus provides cooling.
391
questions
4
votes
1
answer
352
views
What is meant by the statement "Local bypass capacitors are needed to control EMC coupling with heat sink"?
During a talk, not sure what the speaker meant by the statement " We need to add local bypass caps to control EMC coupling with heat sink"
He was referring to the MOSFETs in synchronous ...
- 2,051
0
votes
2
answers
81
views
Where can I find large thru-hole heatsinks like this? [closed]
I'm doing a project with an OPA541 amplifier, and I need to find a heatsink similar to the one in the pictures:
But I only found small ones with a screw hole and legs for soldering, none of the large ...
1
vote
1
answer
102
views
Can a CPU heatsink be used to cool a TO-3P or a TO-220?
I want to know if my thermal design is appropriate for dissipating 72W of heat while keeping the junction temperature below 150 °C (I am trying to cool an SFH154 that comes in a TO-3P package). My ...
- 553
1
vote
2
answers
69
views
Step-down conversion materials
I have an ac adapter on which I would like to reduce the output, from 24 vdc to let's say 6 vdc. What type of diodes should I use and how many? What about heat dissipation?
- 11
4
votes
2
answers
154
views
Copper braid as heatsink
Somebody recently asked me about this headlight: https://www.hsd-il.com/products/h7-72w-8000lm-led-car-headlight-bulbs-cree-led-chips-6500k-drl-copper-belt-headlights-12v-24v
Interesting. I'm not ...
- 51
0
votes
1
answer
106
views
What is the black, finned, metal part in this picture of a board?
Can someone explain what this black part is?
This a WLAN module.
- 217
2
votes
1
answer
87
views
LED lights become darker? [closed]
I build myself a light with many small LEDs. They are quite powerful. I superglued ever LED board (the LEDs where in parts of 3 on a small circuit board) to an aluminium piece to dissipate the heat.
...
0
votes
1
answer
51
views
Possible fixes to a power supply thermals issue
The question applies to a buck converter design on my board:
Here is a 3D view of this section:
Layout of this section:
L1:
L2:
Layer 3 is power and layer 4 is again a full ground plane.
Here is ...
- 539
0
votes
2
answers
122
views
Is it safe to connect metal body capacitors with a metal heatsink?
I have multiple metal case capacitors that I need to cool. The thermal tape I use is conductive (carbon based). Also larger heatsink on the left might touch capacitors on the left side. The question ...
1
vote
2
answers
31
views
How to use units given for heatsink thermal resistance?
In looking for a heatsink I came across a company giving the thermal resistance of extrusions in °C/W/3in. How do I use this?
Say I use an extrusion with a specification of 1.5 °C/W/3in and get it ...
- 165
0
votes
1
answer
73
views
Does voltage drop resistor affect power dissipation?
I need to power an RFID from 24 V DC voltage. The RFID requires max. 9 V and max. 120 mA. The RFID suggests a 7809 linear voltage regulator. I thought too much and I want to use a 7809 because if I ...
- 115
2
votes
1
answer
175
views
Why is my DC/DC converter getting super hot?
I need to supply an evaluation kit at 32 VDC +- 10 % from a 48 VDC battery. The power supply of the kit is rated at 60 W with spikes at 150 W lasting 100 ms (it controls motors).
I have choosen the ...
- 467
0
votes
1
answer
68
views
Heat sink thermal resistance
Is there any way to figure out the thermal resistance of a heat sink without using a datasheet or using it in an actual circuit? I mean, simply by knowing its dimensions and material.
-1
votes
1
answer
66
views
Heatsink size calculation
Let's say I found a random heatsink with no name or model or anything else from which I can find a datasheet and get its thermal resistance. Therefore, simply by knowing its sizes, how can I calculate ...
0
votes
1
answer
60
views
How can I specify in Altium to leave out the dielectric layer for a portion of the board?
I am trying to replace the dielectic layer in just a portion of the board and instead have that just be more copper. The idea is to essentially allow the PCB to use anything it lays flat on to be a ...
- 187
0
votes
1
answer
63
views
How should fuses be used for MOSFET temperature protection?
I am using high voltage MOSFET in TO-220 package with a heatsink like this one:
Under normal conditions, the temperature of heatsink does not exceed 90 degrees.
My MOSFET can run up to 120 degress ...
- 55
0
votes
1
answer
85
views
How do I use a heatsink in a sealed enclosure?
I'm working on a project with a set of individual LEDs (datasheet) permanently set up in an outside setting in winter, at night.
I need to build separate enclosures for each of the LEDs because they ...
- 19
1
vote
2
answers
111
views
What power supply do I need for this LED driver?
I'm putting together a project where I'll be driving 4 x 10W RGB LEDs (these ones) with one PicoBuck LED driver. I'll be using all three channels on the LEDs at the same time and controlling dimming ...
- 19
0
votes
3
answers
117
views
Heatsink needed to keep my resistor from damaging due to heat
I am looking to find an appropriate range of heatsink selections to maintain my resistor from damage due to heat. I am using a flat plate (SS) resistor from ARCOL (TFBR900). It is rated for a 900 ...
- 3
0
votes
0
answers
77
views
Attach heat sink to cpu cooler in order to decrease CPU temperature
The best SMALL FACTOR cpu cooler that I have found so far is this one:
I am building a portable PC; therefore, the smaller the better. I have already checked the specifications and that cpu Noctua ...
- 547
12
votes
4
answers
2k
views
Why are these SMD heatsinks designed to not touch the IC?
I am using a 7106DG heatsink to dissipate the heat from an IC. It looks just like in its datasheet:
It leaves a gap between the IC and the heatsink, and the datasheet even mentions it, but I guess no ...
- 2,052
1
vote
1
answer
71
views
Copper Weight/Copper Pour Usability in Thermal Management
I'm trying to think of a way to decrease the temperature that my PCB is running at, but I don't want to add a heatsink if I don't have too since I want this board to have as low of a profile as ...
- 993
2
votes
3
answers
172
views
How does junction to case thermal resistance depend on PCB?
Shouldn't the junction to case (top or bottom) thermal resistance depend only on package or IC internals? How do the PCB details play a role as mentioned in footnote 1?
- 2,051
6
votes
2
answers
834
views
Why is the thermal resistance of copper shown higher than FR4 in below snap?
I see similar W and L for both Cu and FR4.
Why is the Cu thermal resistance shown higher than FR4? Is it because of Ounz difference?
1 Oz Copper= 34.8um.
FR4 seems to have more thickness-> How ...
- 2,051
1
vote
1
answer
103
views
How to remove and replace fiberglass based thermal conductive adhesive tape/sheet on heat sink
I'm working on troubleshooting a PSU and came across a fiberglass like thermal conductive adhesive tape/sheet (soft beige) in between the TO-220 power MOSFETs and the heat sink as shown in the photo. ...
- 111
9
votes
4
answers
2k
views
Installing heatsink on a bridge rectifier: which side of the rectifier should it be installed on?
I'm going to install a heatsink on a KBU810 bridge rectifier. As the picture shows, the leads are closer the face with markings on it.
I wonder if one of the two faces is the preferred site for ...
- 715
0
votes
3
answers
113
views
How to calculate heatsink for this power supply?
..to be updated
I will use a power supply inside an enclosure. But I saw some people are screwing these supplies to heatsinks where the bottom of the supply faces the heatsink.
But nothing is ...
- 1,514
0
votes
1
answer
62
views
RF Module Gets Too Hot
I'm using the RFM98PW-433S2 1W(+30dBm) 433MHz RF module. After a couple of minutes of working the module gets to above 70°C temperature. Probably reaches 90°C and above after couple more minutes. I ...
- 53
6
votes
2
answers
1k
views
Is raising a hot Zener diode from the PCB (for better ventilation) a bad idea?
Whenever I rework a Zener diode which has been running too hot (i.e. failed), I like to replace it with a higher-power equivalent when possible, and (if through-hole) raise it slightly off the board ...
- 11.7k
1
vote
3
answers
85
views
How can a complex shape's heat sink thermal resistance be determined?
I need a heat sink with a thermal resistance of 0.7 °C/W/3" or less. C/W/3" represents how many degrees Celsius per watt a 3" long section of heat sink can dissipate without exceeding a ...
- 113
1
vote
3
answers
696
views
does a larger or smaller C/W thermal resistance value indicate greater heat dissipation
I need help understanding the heat sink thermal resistance specification. Does a larger thermal resistance value indicate it will dissipate more or less heat?
- 113
2
votes
2
answers
1k
views
Can PCB dissipate heat from MOSFET so that a heatsink is not needed
I am using a DMP3007 as a reverse polarity and over voltage MOSFET. The maximum planned load is 10 A and voltage may vary as the load is a constant current load.
simulate this circuit – ...
- 1,522
0
votes
0
answers
59
views
Grounding of heatsink for SiC MOSFETS half-bridge
I was working on SiC Mosfet half bridge for dual active bridge, Each half bridge has two SiC MOSFETS Rds0n=0.035 mohm , the bus voltage peak is 600VDC on the primary side. and I was wondering should I ...
- 303
1
vote
2
answers
253
views
Electric-grade gel / silicone to provide physical protection for circuit boards from damage
Not looking for a brand or product (unless allowed to ask) just the generic name for electric-grade gel / silicone that can be poured on the circuit board or embed the circuit-board in it. It would ...
- 123
0
votes
2
answers
157
views
Can two IRLZ44N MOSFETs in parallel handle a current of 20 A without heat sink?
Can two IRLZ44N MOSFETs in parallel handle a current of 20 A without a heat sink?
The Vgs command is a square wave at a frequency of 70 Hz.
Do I need to attach two big heat sinks or not?
Will my two ...
0
votes
2
answers
69
views
Understanding Power Diodes and Heatsinks
I am working on reverse engineering and understanding a circuit board from the 1970s. I don't have a schematic diagram from the manufacturer. This board has an unmarked power diode that has a flange ...
- 293
6
votes
3
answers
591
views
What's the right replacement for vintage "glass cloth insulation" that transfers heat in Variac?
I ripped apart a broken 1950s-era Variac autotransformer to diagnose an internal short in the core, and found a layer of gooey insulating fabric mat between the coil/taps and the mounting plate:
The ...
- 1,093
2
votes
2
answers
98
views
Is my heat sink calculation for the LM317 correct?
Using the formula PowerDissipated = (Vin - Vout) * Iout where:
Vin = 12 V
Vout = 2 V
Iout = 450 mA
Power dissipated = (12 - 2) x 0.45 = 4.5 W
And heat sink value = (...
- 77
1
vote
1
answer
96
views
Mica Insulator for TO-220 Grounded Heat Sink
If I have a three terminal TO-220 voltage regulator where the center terminal and heat sink are connected ground terminals, is there any reason not to mount the heat sink directly to an aluminum ...
0
votes
3
answers
82
views
Is the melting point of pure indium too low to safely use to solder together a custom copper heatsink to be used ontop of motherboard mosfets?
Is the melting point of pure indium too low to safely use Indium to solder together a custom copper heatsink that will then be used ontop a motherboard mosfet?
In other words, can the mosfets get hot ...
0
votes
2
answers
127
views
Heat sink sizing for LDMOS
There are many heatsink calculation Q&A's on SE that I've looked through. One very reasonable answer tells me that I can calculate heatsink C/W as follows: $$\frac{T_j - T_a}{P_d} - R_{JC} = R_{...
- 774
0
votes
3
answers
121
views
How to calculate if flyback diode needs heatsink?
I'm designing a circuit for automotive use, where I control various kinds of inductive loads (motors, solenoids, etc) up to 20A (Máx). In the design i'm looking into using 2 SMD N channel MOSFET in ...
1
vote
1
answer
70
views
How can I reduce the power dissipated across this MOSFET without affecting avalanche?
previous and very relevant question here. I want to reduce or remove entirely the heatsink that is attached to my switching MOSFET. It heats up due to the back-EMF generated by the large inductor that ...
- 561
1
vote
3
answers
332
views
Can you connect two lm317's either in series or parallel to help spread out heat?
I am designing an adjustable voltage regulator.
The regulator will have be able to swith between max Vout of 9V, 12V, 15V and 18V and will have a variable resistor that can adjust the voltage from 1....
- 77
0
votes
2
answers
321
views
LM338 gets very hot
I am trying make a variable voltage supply using part of this circuit:
Instead of a transformer and a rectifier, I am using a solar panel, which gives 37 V (open circuit) and about 30 V with a load. ...
- 1
3
votes
1
answer
55
views
Thermal circuit for shared heatsink
I am following this video from EEV blog where he talks about calculating heatsinks and I noticed that he does not talk about multiple components sharing a single heatsink. I have lurked around the ...
- 503
1
vote
1
answer
161
views
DC solenoid overheat protection
I got 40 DC solenoids (12 V, 2 A) and each solenoid may be turned on for max. 5 seconds every couple of minutes or even more. Does this implementation require that an overheat protection should be ...
- 35
0
votes
0
answers
48
views
Peltier cooling calculation - Help ! :)
I have gone through many of online blogs and websites for guidelines about selecting Peltiers but somehow I am still lost in the middle. I am still missing major numbers to be able to select which ...
- 1
0
votes
0
answers
83
views
Heatsink calculation for a MOSFET in active mode
Actually I am working on a project to create an electronic load for power supplies, batteries... testing. The circuit is already designed but I am working now in the heat disipation of the mosfet in ...
0
votes
1
answer
31
views
is connecting high end high power leds in series feasible and are there light quality or other issues
i'm building high power high CRI cine lighting mostly to illuminate softboxes and have chosen Cree XLamp CMT2850 LED 1400mA 36V (Fidelity 95plus CRI).
I plan to build about 12 units for the studio.
I ...
