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Questions tagged [thermal]

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

21
votes
8answers
5k 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
votes
4answers
76 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
vote
2answers
49 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
vote
1answer
37 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 ...
-1
votes
0answers
26 views

VIAS connecting style [duplicate]

why does Altium has via connection style as thermal relief (with air gap), whats the point? i mean we don't solder vias anyway, wouldn't it be better to have them direct connect? i mean whats the ...
-7
votes
1answer
102 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....
0
votes
3answers
78 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
votes
1answer
66 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
116 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
vote
3answers
77 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
votes
5answers
130 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
vote
4answers
92 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
votes
1answer
55 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
33 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
vote
2answers
92 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
115 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
votes
3answers
39 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
votes
2answers
74 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
vote
2answers
187 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
votes
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
votes
2answers
57 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
37 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
votes
0answers
126 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
votes
0answers
27 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
votes
1answer
35 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 ...
-1
votes
4answers
253 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
votes
1answer
39 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
116 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 ...
0
votes
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
votes
2answers
72 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
47 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
89 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 ...
0
votes
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
votes
0answers
55 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
votes
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
vote
1answer
135 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
540 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
326 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 ...
1
vote
2answers
161 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
votes
1answer
585 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
votes
0answers
49 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
vote
2answers
104 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
90 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 ...
3
votes
2answers
837 views

Thermal Paste on Cold Side of Peltier Freezing and not transferring “Heat”, what gives?

I am running a peltier element, and on the cold side an aluminum heat sink to effectively spread out the cool surface to the maximum possible surface area. I just bought this new thermal paste: ...
1
vote
2answers
378 views

Liquid Metal Thermal “Thermal Grease” on a Peltier Element?

I was wondering if Liquid Metal Thermal Grease could be placed on a peltier's hot side to better conduct heat from the hot side to the heat sink. I know that aluminum is "Eaten" away by the thermal ...
0
votes
1answer
2k views

Nichrome wire gauge calculation

I know what battery I wish to use (3.7 V 140 mAh which I can swap for larger mAh battery) I know what length of wire (3.5 inches or 7 inches depending on which ever would work better) I know what ...
18
votes
1answer
1k views

TO-92 not getting hot enough

I am controlling a DC fan by an AVR MCU and I am curious about the thermal characteristics of a 2N3904 NPN transistor over which the fan is connected. Reading the transistor's datasheet, I find the ...
0
votes
2answers
143 views

How to increase thermal shock resistance of the electronics components?

How to increase thermal shock resistance of the electronics components assembled on the PCB? Is there any material (or method) for increasing the thermal shock resistance of components? Best Regards, ...
1
vote
2answers
203 views

Will stacked Peltiers produce a greater dT? [duplicate]

I am using this peltier device to ramp an aluminum plate down to -10C in a vacuum environment. I chose this particular device because it had the largest 'Qout' of any single-stage peltier I could find ...