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Questions tagged [thermal]

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

2
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1answer
83 views

Name of fabric insulator found inside motors

What is the name of the fabric sleeve insulator used for components (typically fuses) and solder joints found inside motor windings? Can regular heat shrink tubing be used as a substitute? Image by ...
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2answers
79 views

Can a thermal fuse of a higher rated current be used safely?

I want to replace a 115°C 250V 2A thermal fuse used in a fan motor. The only fuses available locally are 115°C 277V 15A. Can I use the higher current rated thermal fuse? Since it is a thermal fuse, I ...
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0answers
12 views

BGA package LTM8064 switching regulator thermal management Consideration

I'm using ltm8064 for an application which required 24V, 4 amp output which causes 7W of heat dissipation. In the datasheet thermal resistance of junc to case(bottom) is 2.2 c/w and junc to board in 6 ...
4
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1answer
126 views

IC product lifetime as function of junction temperature

If an IC is rated for an absolute maximum junction temperature of say 170 Celsius, obviously it is not recommended to operate there - but how drastically is product lifetime impacted if we are close, ...
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2answers
58 views

May I use a smaller wattage resistor as mosfet's gate driver for a very short time?

In a H-Bridge circuit, i am using gate resistors on all the mosfets. My calculations for one of them, Gate voltage 4.5 V and Resistor 100 ohm gives me 45 mA, means 203 mW. In a pulse of 16 us i ...
0
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1answer
35 views

Thermal hysteresis of shunt regulator

What is the meaning of the "Thermal hysteresis" in shunt regulator datasheet ? Will it contribute to output tolerance ? FYI: It's TL4050C50-Q1 datasheet.
18
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3answers
4k views

Why do 0 dB attenuators exist?

I am reading this paper : Upgrade of a low-temperature scanning tunneling microscope for electron-spin resonance and found that for thermalization, they use 0 dB attenuators. Page 6: Having the ...
23
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8answers
6k views

How to solder a 70 °C (158 °F) thermal / temperature fuse

For my DMX project (schematics is not important), I soldered this temperature fuse which has just two leads (see picture below). The fuse doesn't work (meaning it does not conduct electricity) ... ...
0
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4answers
87 views

BLDC Motor Performance at high altitude?

How does a BLDC motor performance change at high altitude where the air density is really low? For example, say I have a given BLDC motor with given torque-RPM performance curves. Now, I assume these ...
1
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2answers
57 views

Collisions of Thermal Impedances

As shown in the picture below, thermal impedances of an IGBT device depends on the temperature. However, there is a strange phenomenon as follows. While with increasing the temperature, steady-state ...
1
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1answer
40 views

Do thermal cutoffs exist that would work with a line that is 40-75V 0.5A and a max temp of ~85°C?

I have a bunch of COB LEDs that I am going to wire in series using an LED driver. The driver gives off between 40-75V and 0.5A max. The circuit should run around 70V and 0.5A. Due to space ...
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1answer
108 views

Light source that withstands extreme conditions [closed]

I am designing an aircraft obstruction light, and Federal Aviation Administration (FAA) requires crazy requirements for their standards. One standard goes as following (From FAA AC 150/5345-43H): 4....
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3answers
103 views

thermal fuse as electrical fuse

I am trying to understand the spec of a Datasheet of a thermal fuse. for example the one below : https://nl.farnell.com/panasonic-electronic-components/eyp2bn134/fuse-thermal-cut-off-2a/dp/1832031 ...
0
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1answer
111 views

Waterproofing MLX90640 far infrared thermal sensor

I would like to use the MLX90640 far infrared thermal sensor array on a car as a "night vision" camera. Since glass blocks thermal radiation I have to install it outside the cabin. Is it possible to ...
3
votes
1answer
158 views

PCB power supply layout considerations

I'm designing a circuit that steps down 230v AC to 12v DC and then uses an MCP73213 IC to charge a 7.4v li-po battery. There is also functionality to switch over to the battery supply if there is no ...
1
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3answers
164 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 ...
0
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5answers
138 views

How hot should wires get?

I am using 10 AWG wire to power a BLDC motor, and these wires can get quite hot. When an IC is intended for high power uses, it is common practice to put a heat sink on it, but what about for wires? ...
1
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4answers
214 views

Replace a one shot thermal fuse with a resetting one [closed]

My mother owns a device for drying fruits and stuff. Now every year or so, the thermal fuse breaks. I'm always checking if the fan is damages or something else, but the device is always fine. It is ...
0
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1answer
66 views

Multiple Parallel LED Drivers with Single Thermal Derating NTC Thermistor

I am looking at powering Some multi color High power LEDs e.g LED engin LZ4 or LZ7 (probably a string of five) using a tps92691 based Circuit these being high power leds it seems wise to include ...
0
votes
1answer
34 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, ...
1
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2answers
99 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 ...
2
votes
1answer
148 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 ...
0
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3answers
41 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 ...
0
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2answers
78 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 ...
8
votes
3answers
1k views

OP1678 running hot

I have built a circuit that converts a 0-5 V signal to a +/- 9 volt signal using OPA1678 Op-Amps (original design from Here). The 0-5V signal is received from a 10k potentiometer across the +5V and ...
1
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2answers
271 views

Use Thermal Relief in High Current Traces?

I'm designing a SMPS PCB with a pretty high current goal (using it to power multiple servos). Using KiCAD, I decided to use solid fills on the pads of the high current areas, but by default thermal ...
0
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1answer
45 views

Is thermally conductive epoxy needed if long settling time is acceptable?

I'm using SMD based analog temperature measuremet ICs (a version of the old TMP36). It will be mounted on a tiny and thin (.5mm) PCB I've cut to hold the IC and a few mfgr recommended parts and a 3 ...
0
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2answers
60 views

Thermal parameters for the LM1117

Looking at the datasheet for the LM1117 regulator, on page 18 to 20 there's a table of various layouts for copper cooling planes for the LM1117 in SOT-223 and TO-252 packages. Comparing figures 30 and ...
0
votes
1answer
52 views

Compact thermostat for VCO temperature stability

So I have a voltage controlled oscillator with an exponential input made using the THAT2181 VCA IC. The schematic is shown below - the THAT2181 IC is used to change the C4 capacitor charging current ...
0
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0answers
241 views

Thermal resistance of a wire of copper

I was reading a book about thermal heat conduction and resistance, when I found the next example: Try to calculate the temperature of a 4-in(0.1m) piece of #12 copper wire at the end that is being ...
0
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0answers
31 views

Is the V_t in this document regular Thermal voltage?

I have been looking at this short document. https://pdfs.semanticscholar.org/c490/4c04a7be1d675e360409178da71a1253f6d8.pdf It uses V_t and defines it as thermal voltage of a transistor. It does not ...
0
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1answer
36 views

LM 56 temperature trip point resistor selection

I'm having a hard time grasping on how to calculate the values for resistors R1 R2 and R3 in the typical application diagram pg.2 in the data sheet. Could some one break down the calculation steps ...
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4answers
539 views

Is there a way to define 26mV thermal voltage with simple words [closed]

This 26mV thermal voltage at room temperature is used in non-linear diode equation. I tried to learn about it to see what it means without getting involved in too much physics but failed to find a ...
0
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1answer
43 views

Connector current/thermal rating

This question started as a design specific question but is (now) more of a general question going forward onto other PCB product designs... For now, I am designing an I/O PCB and want to mix supply ...
2
votes
2answers
138 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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0answers
49 views

Non-uniform temperatue distribution

Please assume a semiconductor chip like IGBT or MOSFET heated by a specific power loss. It is found that the more the power loss is, the more severe the chip's temperature distribution non-uniformity ...
0
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2answers
76 views

How Can I Find “temperature coefficient” of a Battery?

I am studying mathematical modeling of a battery in simulink and for this it is necessary to determine some parameters. I'm stuck in the part where I need to determine an alpha parameter, which would ...
0
votes
1answer
48 views

Thermo Electric Cooler(TEC) for ICs

I am designing a 9u rack server with optical ports. I want to implement Thermo Electric Cooler(TEC) for cooling the ICs(switches, FPGAs) on board, so that I can reduce the fan speeds. Is this a good ...
3
votes
1answer
102 views

MOSFET mechanism of failure: was it the heat?

I am debugging a failed MOSFET (IRF6662), and in the process of doing so, am having difficulty understanding fully the thermal behaviour of the FETs. Two FETs used for DC switching both failed short ...
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0answers
16 views

Which battery to use to charge my arduino project?

when you are connecting ESP 8266 to an SMD UNO R3 Arduino board along with a sound sensor and a thermal sensor MLX 90614 , how much will be the range of power required to run this project smoothely on ...
0
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0answers
56 views

Uneven chip temperature

When injecting a uniform power dissipation in a chip of IGBT power electronics modules by finite element method (FEM) in COMSOL (a good software for thermal analysis), a non-uniform temperature ...
9
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5answers
3k views

In a CPU, does the speed of a calculation affect the heat generated?

Take as an example a CPU that is capable of changing its clock speed, like a modern computer CPU (Intel, AMD, whatever). When it does a certain calculation at a particular clock speed, does it ...
1
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1answer
184 views

Thermal Fuse Crimp material

I speculate this is just barely an EE question, but I'll risk it anyway: I'm replacing a set of 175C 10A thermal fuses (with 172C 10A actually). At this temperature / current range, do we need ...
3
votes
3answers
645 views

What is the difference between a resistor and a heating element?

As far as I know, a resistor and a heating element are the same thing. But one, the resistor, seems to limit the current in the circuit while the other, the heating element, draws more current and ...
5
votes
5answers
522 views

How closely should I space my thermal vias?

How closely do you pack your thermal vias? I know that more vias divides the amount of heat each via can move and that smaller vias allows more vias to be packed together. Knowing this, it seems ...
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2answers
233 views

Thermal voltage

In Shockley diode equation Vt is the thermal voltage and equals KT/q. In wiki article 'T' is defined as the absolute temperature of the p-n junction.As far as I Know the junction temperature is ...
3
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1answer
587 views

Thermal impedance too high for proper use

I'm not sure to correctly understand the datasheet of Traco THN24 family. I read this: Thermal impedance – Natural convection 17.6°C/W but the DCDC is rated for 20W without de-rating (100% output ...
0
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0answers
50 views

Can I expect a probe thermometer to still work if I cut it short?

I have a kitchen probe thermometer, a bit like this one It's overly long for my purposes, and takes an annoyingly long time to record a stable value. I assume this is because it takes a while for the ...
1
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2answers
116 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
vote
3answers
91 views

Why do high current wires have fabric/nyon sheathes?

I saw two wires going into a halogen light bulb whose outer sheathes were not a plastic (like PVC, or polyurethane), but rather a woven fabric (like a nylon shoelace). Why is woven fabric better for ...