Questions tagged [thermal]

Relating to temperature rise, the flow of heat, or cooling of components

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2answers
1k views

LM317 - Calculate dissipation due to voltage drop

If I use a linear voltage regulator as LM317: Input voltage = 24 V Output voltage = 5 V (so a voltage drop of 19 V) Mean load = 480 mA (peak load = 700 mA) From the datasheet, I read that maximum ...
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0answers
12 views

How to use MLX90640 thermal camera code for a AMG8833 thermal camera?

So I want to use the AMG8833 sensor with my raspberry pi and some machine learning code, but the code was using the platypush package which is meant for the MLX90640 thermal camera. But after some ...
7
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3answers
228 views

Warming PCB in cold environment using SMD components only

I made a sensor board that needs to operate at about -55 degrees Celcius. Unfortunately, its key component often malfunctions when the circuit is cooled for days at the temperature and then powered up....
0
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3answers
139 views

Thermal resistance - Temperature transistor

I have a transistor with Vsupply = 24VDC, VCEO = 45VDC, ICE = 20mA. How to calculate the delta T (rise in temperature) of this transistor. I would like to know what thermal resistance I may have at ...
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2answers
233 views

Where would Iceo flow through and would it cause thermal runaway?

I was reading this page about thermal run away. And it mentions: Due to increase in the temperature of collector junction, Ico will increase, Vbe will decrease. But for Ico to increase Ic and ...
1
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2answers
60 views

Temperature Sensor Selection for temp range of 160C to 240C with 1C Accuracy

I am attempting to select a temperature sensor for a controlled heating application. The sensor will need to be inserted into a chamber with a cartridge heater and steel ball bearings inside of some ...
0
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2answers
138 views

Ways to thermally manage a small enclosure?

hopefully this is an okay place to ask this question, but anyway, I'm working on a project to measure efficiency of a mono-crystalline solar cell based off temperature in the enclosure. The solar cell ...
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0answers
54 views

How to simulate flip flop noise

Or is flip flop noisy at all? would you simluate its noise as you would do with a strong arm comparator? Why is strong arm comparator noisy but not a flip flop?
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0answers
35 views

Advice on thermoelectric generators

Hey everyone I was curious if you could help me. There maybe several questions in this so bear with me. Btw I am not an engineer so try and keep it simple please. What variables are needed to find how ...
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2answers
177 views

Very high temperature (>500C) IC packages

I was looking for IC packages where I can mount a small wafer (3mmx3mm) wire bond to the leads of the package and conduct operation at 500C. I have contacted couple of companies which do ceramic IC ...
18
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3answers
43k views

How do filament LED bulbs work, looking very similar to incandescent bulbs?

Filament LED bulbs use very narrow strips containing the LED, which look similar to filaments of an old incandescent bulb: They look like a normal bulb with large "old-style" coal filaments, and are ...
0
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2answers
43 views

Thermal Vias Specification Design

An AD ADA4622-1 with LFCSP8 Package shows as Thermal Specification a "2 Layer Board with 2x2 Vias". What do this exactly means? It is a pcb for the exposed pad pin with 4 vias distributed as a 2x2 ...
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0answers
24 views

Thermal resistance of Thermal Interface Material

Can anyone please give information how to calculate the thermal resistance of SIL PAD "TSP A2000" from make Berguist. from The data sheet its specified thinness is 0.254mm, Thermal conductivity (W/m-...
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2answers
58 views

Does only wiring 2 poles of a 3 pole overload relay have any effect?

When wiring a single phase starter, they tend to jumper the overload such that all phases of the overload are used. Now, considering that the overload has 3 separate bimetal strips all connected to ...
1
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0answers
28 views

lm35 Temperature Reading increasing with Hot-melt adhesive (Calculations check needed?)

I have one question with this topic: lm35 Temperature Readings are not right after sealing with Hot-melt adhesive (How mush has it Soldering max Temp toleration ?) it answered by this (Thanks from @...
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0answers
36 views

Junction Temperature Estimation Error

When predicting the junction temperature (Tj) of semiconductor chips (for example IGBTs) by available thermal models such as FEM simulations, how much is the maximum permissible Tj estimation error ...
3
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2answers
189 views

Temporary thermal adhesive for PCB measurement

I am making an examination on the effects of adding cooling to some existing electronics (making an comparison between having no cooling of the electronics and adding a heatsink or heatpipe + heatsink)...
1
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2answers
207 views

Hot-plug protection: series resistor thermal considerations

I have a circuit in place for the Linear Technology LT3502A switching regulator (datasheet here). To prevent blowing up the whole thing during hot-plugging, I have chosen to add a small parallel ...
1
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0answers
76 views

Why are there no nichrome resistor pastes?

Nichrome wire is commonly used for wire coil heating elements. Other heating elements are formed by screen printing a pattern of "resistor paste" onto a dielectric coated substrate. These pastes are ...
2
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3answers
120 views

Heatsink on top of SMD plastic IC or bottom of PCB?

I often do designing power modules and always wonder if there is some kind of rule how to properly cool SMD devices. I always look at final products from other companies and some are placing heatsink ...
0
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1answer
106 views

How to determine the right trip point of thermal cutoff for 1/4 hp 3A 115V single phase ac motor

The Thermal fuse blew in my Ryobi DP102L drill press motor, while I was drum sanding. There were no markings on the fuse. The single phase induction motor is 1/4hp 3A (no load) 1750rpm on 115V AC, ...
0
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1answer
73 views

How to power a nickel chromium wire to produce heat without burning the power adpapter

I want to build a toaster just for fun. I want to buy a nickel chromium wire to heat the toaster's plate. How to avoid burning my power adapter cuz the resistance is too low. I currently have a ...
15
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5answers
2k views

SMD IC mounted upside-down inside a drill hole for extreme low-profile requirements

I don't know if the title is descriptive enough, but I came across this PCB and could stop to wonder about its brilliant design. It is an aftermarket trigger controller for an airsoft gun that works ...
1
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1answer
174 views

Will PCB board house accept this QFN thermal pad via design (KiCad)?

I am going to be ordering this board from JLCPCB which has some 0.2 mm hole diameter thermal vias on a QFN pad, and it says on their capabilities page that the smallest via hole size is 0.3 mm, BUT ...
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1answer
292 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 ...
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3answers
107 views

Interpreting results of a thermal camera - what should I expect to be hot?

I'm not a trained electrician, but I got my hands on a thermal camera to play with. Its existing documentation didn't help me quite understand what's going on when I see a hotspot. What components can ...
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4answers
399 views

How do thermal tapes transfer heat despite their low thermal conductivity?

I found myself needing to attach small heatsinks to Mosfets and CC power regulators. Also some high-power diodes. Today I have learnt that thermal compounds, even best in the market, are dozens of ...
1
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3answers
99 views

Do unused relay pins help with heat dissipation?

I have been using DPDT relays to control high-current loads (~15 A at 240 Vrms) though I am only using them in a SPST, NO fashion; that is, the load is disconnected when the coil is de-energized, and ...
28
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6answers
10k views

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. ...
1
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2answers
53 views

Thermal noise voltage measured by an impedance matched ADC

I have a question regarding the thermal noise voltage measured by an impedance matched ADC. In the figure above, I have a simplified circuit with a source impedance (on the left) and an ADC (on the ...
2
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1answer
1k views

N-channel mosfet calculations

I am in the process of selecting a suitable FET to switch a resistive load (LEDs), triggered by a 3.3v MCU signal. The schematic would be: However, I am having some trouble with my (rough) ...
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0answers
71 views

How to calculate MOSFET temperature increase in PCB

I want to calculate MOSFET(DATASHEET) temperature increase for PCB. MOSFET - FDD86250_F085-D Totally 13 MOSFET's will be mounted in PCB. At the same time, maximum 8 MOSFET's will be used in PCB 1, ...
3
votes
1answer
367 views

LM3876 Heatsink

Could someone point me to a suitable heatsink for an LM3876 amplifier? Or, even better, a heatsink that I could attach two chips to? Perusing through Mouser's catalog was a bit overwhelming. ...
2
votes
1answer
68 views

The Thermal relief consideration for TVS diode (for ESD protection)

I am designing a print which has some mircofit connectors, I have placed TVS very close to the connectors on the print and the ground pad connected with a GND polygon directly, this polyon connects ...
3
votes
2answers
3k views

What are thermals?

I was looking through various options available for Eagle CAD through-hole and SMD pads and I noticed a "thermals" option. The documentation wasn't much help in determining their function other than ...
1
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3answers
52 views

Need help in cable temperature calculations

I am trying to calculate how hot will a 0.6m long 28AWG wire carrying a load of 12VDC, 0.2A get. I understand that are other factors such as environment cooling rate, thermal resistance between air ...
0
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3answers
39 views

Calculating Junction Temp of Switching Regulator

I was looking at TI web bench to find a regulator, my question is my calculation is correct and if it is why we have different value on webbench. The IC is TPS565208 P = (Vout - Vin)*Iout => (12-...
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0answers
12 views

Infineon IPOSIM tool for IGBT thermal loss calculations

I used the infineon IPOSIM power tool for simulating a motor drive for my required conditions and got the results for a custom input drive cycle. The results were given as power dissipation per IGBT(...
1
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1answer
37 views

Application based Heat sink design for Power diode

Instead of having a heatsink directly connected to the diode, I want to have a 2 mm layer of cold rolled steel in between case and heat sink(aluminium){for waterproofing as needed in the application}. ...
6
votes
3answers
447 views

Heatsink on underside of PCB

I have prototyped some DC-DC converter modules, and they work well. However due to size, I don't have a huge amount of copper pour for them to dissipate their heat. I have used 2oz copper but the ...
2
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1answer
57 views

Would leakage through a JFET create thermal noise

The impedance through the gate of a JFET is very high and leakage current very small. Would this impedance act like a large resistor creating thermal noise? Would this be a low noise way of ...
0
votes
1answer
72 views

Colpitts oscillator: how to reduce amplitude thermal drift?

I have built this circuit, supply ±12V: I am using a LM6172 amplifier. I have found the transfer function of the filter involved: \$H(j\omega)=\frac{1}{1 + \frac{R_3}{R_1} - L\omega^2(C_2+C_1\frac{...
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0answers
21 views

Heat transfer coefficient in a Module Baseplate

Today, for example in a power IGBT module cooled by a heatsink, it has been found that the heat transfer coefficient (htc) distribution may not be uniform across the bottom surface of the module ...
0
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1answer
41 views

Thermal resistance Junction - Maximum Power dissipation

I want to understand the real meaning of the parameter 'Thermal Resistance Junction to Air (°C/W) to calculate the power dissipation. So for example if the value of this parameter is 250°C/W, should I ...
-2
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1answer
64 views

Resources for finding thermal impedances for common IC packages

I'm just looking for some extra resources for thermal impedances of JEDEC standardized packages. I've already found one such article posted by JRC, https://www.njr.com/semicon/package/thermal.html , ...
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2answers
94 views

Thermal Glue solvent

I have a PCB with many chips on it - it's a "hashboard" for an ASIC bitcoin miner. There are 63 chips on every hashboard, and each chip has a small heatsink on it. I tried heating the heatsinks with ...
4
votes
2answers
54 views

POWER MOSFET - Thermal Design

i have some doubts about with this thermal design? first, the calculations and infos: My load (a motor) uses an average current of 7A, I could not measure the current peak at the beginning of the ...
0
votes
1answer
45 views

Wire gauge and combined wires for 3D printer hotend through PCB

So I've been designing a wiring harness PCB for my 3D printer to provide connections and easily swappable tools. I settled on a TE 34-pin connector to use as input on the PCB. The current design ...
0
votes
1answer
39 views

Cold activated heater control

I would like to build a simple control circuit for a 12v silicone heating pad. I think what I'm looking to make is a thermally controlled relay: I want current to flow when the temperature is below ...
0
votes
1answer
83 views

LD1117V33 voltage regulator heatsink, thermal paste needed?

I want to screw a heatsink to my LD1117V33 voltage regulator. It's a normal 3mm screw and nothing inbetween. Do I need to use thermal paste or something like that? It will be regulating 12V down to 3....