Questions tagged [heat]

Thermal energy; where it comes from, and how to keep it from damaging components

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2answers
42 views

How to determine electrical energy and the convert it to heat?

I've been stuck on a problem for quite some time now. I really cannot get my head around it. It's been a while for me, and I just recently been taking up a class again in electrical engineering. I've ...
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3answers
165 views

Heat Conduction from ceramic resistor to iron rod

I'm trying to conduct a thermal conductivity test. I've set up an experiment where I take a rod of a given material (steel, for example), measure its cross section, length, extreme temperatures and ...
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2answers
228 views

MOSFET getting hotter than calculated

as the title said, I'm facing this problem. I'm controlling a Peltier element (91.5W at 15V, what should give us aprox. 4A at 12V) with two different MOSFETs: IRF3205 (Rds(on) = 8 mOhm) and FQP30N06 (...
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2answers
149 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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3answers
3k views

How to Attach a Nichrome Wire to a Regular Copper Wire?

I am trying to make a room heater. It comprises of a few coils of nichrome wire connected in parallel with each other and in series with a regulator to control the voltage. I am also having a step-...
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2answers
28 views

thermal conductivity of a liquid cooler

I'm a high school student in a class called EDD, where we design a product and produce a prototype of said product. I have one issue though: My team bit off more than we could chew, and we have no ...
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1answer
76 views

Heat dissipation from pcb

I have a PCB with several power ic's. The pcb is connected to an aluminium plate as a heatsink on the back of the PCB. How can I measure how much heat dissipates from the top of the PCB to the air? ...
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1answer
103 views

Will this battery case be able to sustain 3.5 amps?

I'm trying to make a 10S Li-Ion battery case, and I'm currently wondering if it will be able to sustain a current of 3.5 amps running through it. I like to believe I'm pretty good at electricity, ...
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3answers
1k views

Transformer voltage step-up and heat

A step-up transformer turns a lower alternating voltage to a higher one, while stepping down the current. This is due to the conservation of energy (energy to into the first coil must equal to the ...
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2answers
49 views

Old monitor’s internal power supply works only when heated from the outside…fixable?

I have this old LG Flatron w1934s that worked fine until it‘s power indicator led started flashing, and after a long while the monitor turned then on, if I heated the monitor’s back with something ...
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1answer
214 views

How to design for electrical connection for a food dryer

I am on this project in building food dryer to dry 2 kg fish cracker maximum per use. Based on the calculation, I only need to use power of approximately 60 watt for the heating to achieve the energy ...
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2answers
175 views

Reducing heat dissipation in linear current source used for driving a LED

I'm currently using a linear current source to drive a single LED as in here. In my case (following the notation in the link), VDD is directly connected to a single cell lithium polymer battery, i.e. ...
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3answers
43 views

Thermal Resistance of PSU's heat sinks

I have a non functional PC power supply unit, and I would like to keep its heat sinks, but they have no model or part number in them. Is there a way to estimate, calculate or measure their thermal ...
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2answers
74 views

What resistor type is best for use as a heater?

I'm working on a design that requires I heat a bank of 18650 batteries during their operation. The plan is to mount the batteries along with large axial 2W resistors in to a PCB and using small ...
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0answers
49 views

Resistive heating cuircuit design

I am designing a small (10mm^2) resistive-based heater. I wish to heat a ceramic surface to about 250°C, via some high frequency AC-current. My aim to is have some sort of high-temperature PCB printed ...
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4answers
5k views

Why is the metal tab of a BJT power transistor is always connected to its collector pin?

Until now I thought the metal tab of a BJT power transistor is connected to ground but it seems like it is connected to its own collector pin´as shown in the below illustration: Is there a particular ...
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2answers
174 views

Cost Effective Alternative to IMS(Insulated Metal Substrate)

I am currently working on a project where we are trying to limit costs as much as possible and one of the results of this is trying to avoid using IMS(insulated metal substrate, in this case 0.125" ...
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3answers
36 views

Detecting different heat element power

I have a range of heating elements with different power ratings (i.e. different resistances). Is there a way for my microcontroller to detect what power they are so I can use the microcontroller and a ...
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4answers
2k views

Reliability problems with an array of 91 high-power LEDs

I have designed and printed a 4-layer PCB that accommodates 91 infrared LEDs in a 7x13 rectangular layout. This will be used as a backlight for a machine vision project. I am having a problem where ...
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1answer
4k views

How to calculate the heat dissipated by a battery pack?

I have a battery pack consisting of 720 cells. I want to calculate the heat generated by it. The current of the pack is 345Ah and the pack voltage is 44.4Volts. Each cell has a voltage of 3.7V and ...
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3answers
128 views

Using a small heatsink with a high power LED (50W)

Description I want to use a 50 Watt LED like this one (42mm*40mm) The space to integrate this component is limited. I have only 55mm*55mm*30mm in total. So the LED + Heatsink size must not be higher ...
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3answers
326 views

Motor Voltage and Current Limit of Brushed DC Motor

What fundamentally limits the applicable voltage in a motor? From what I understand, the input to the motor is a relatively constant impedance (since speed is on the order of 100 Hz) and it is ...
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2answers
103 views

Applying heat to a transistor

I witnessed an experiment in which a transistor was connected to an led and a power supply. A lighter was used to heat up the transistor and this reduced the resistance of the circuit and made the ...
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1answer
125 views

Can I simply add a 240V Neutral to SONOFF TH10 when replacing wall thermostat

So, I have purchased a SONOFF TH10 wanting to use it to replace my wall mounted thermostat. The thermostat has 2 connections: Always-Live and Switched-Live (which is activated of course by the ...
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6answers
63k views

My linear voltage regulator is overheating very fast

I'm using a 5 V / 2 A voltage regulator (L78S05) without a heatsink. I'm testing the circuit with a microcontroller (PIC18FXXXX), a few LEDs and a 1 mA piezzo buzzer. The input voltage is aprox. 24 ...
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3answers
173 views

Heat dissipation by convection for ICs placed upside down

I'm currently designing a PCB with a couple of fast electronic elements (600MHz ARM, DDR3 ram etc.) and I'm quite puzzled which layer should those elements be placed upon. The product will be closed ...
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1answer
97 views

Whats the simplest heating surface for a DIY project

I'm trying to make a very small (3x3 cm or less) cup or surface that will heat to around 200C. The surface needs to be dry and I only care about heating the surface and not any particular volume of ...
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5answers
3k views

LM7805 heating up

I maked a schematic for trigger a siren 12v by a signal from Raspberry Pi (GPIO18 PWM 3.3V). All the circuit is powered by a power source of 12v 15A (see the image below). SCHEMATIC UPDATED: It's ...
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1answer
101 views

Electroconductive fabric

Just by looking at the pictures, can anyone help me identify what kind of blanket the copper strips are glued to? The kind of material and composition. Apparently seems to me to be a very thin glass ...
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1answer
121 views

How can a wire have 0 conductivity and 0 resistance?

First post but lurking for over a year I bought some cheap heating pads on EBay a long time ago. 4v wouldn't get all 5 in parallel hot enough and 8v was unbearably hot so they went in the pile of ...
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1answer
57 views

Is heating the nichrome wire with phone battery possible?

I want an nichrome wire to heat instantly red hot when connected with phone battery using 2 copper wires. Do I need any extra circuit to convert the volts into current for heating? (H=I^2Rt) Would ...
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1answer
3k views

Resistor overheating

I have problem with the model of given power limiter (below are the images). Problem is in the red rounded resistor on the last image - that resistor overheats for some reason (I've put 3 ohm one ...
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0answers
87 views

Heat managment of FR-4 PCB

I have now finished the PCB. I want to run 20 LEDs (105 mA 3.3V) with 105 mA and 6.6V for this I have a 1050 mA constant current source. So I connected 10 LEDs in parallel and 2 in series. Does the ...
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3answers
118 views

Can we generate electricity efficiently from a peltier device by supplying heat?

Is it possible to generate electricity from a Peltier device by only supplying heat (not ice)(something above 343 K )? How efficient can it be? Which is more efficient?- Using Peltier device or ...
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2answers
477 views

How is the Correct Surface Load of a Heating Element Determined and Verified?

A heating element should be operated below its maximum surface load (power per surface area.) For a given element, one might be tempted to say the surface load is the power given by Ohm's law divided ...
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1answer
52 views

Taping down cord with duct tape fire hazard?

Curious as to if taping down a cord is a fire hazard. Some cords have very thick insulation and rubber so I do not see how it would be the case. I will try to find the article and update the post if ...
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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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1answer
251 views

Nichrome Wire No Heating with 9V

I have tried connecting one feet of Nichrome 80 wire ( 22 g ) with a 9V battery. Is this enough to heat the wire?
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1answer
48 views

Battery output power calculated from internal resistance - explanation, relation to heat generation and actual power?

On a battery manufacturer specification (https://www.scib.jp/en/product/cell.htm, "High power 10Ah cell") it says: Output power 1800W* (SOC:50%, 10s, 25°C), *This value is calculated from the internal ...
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2answers
71 views

Arduino incubator

For my project I am building an incubator using Arduino. I use a DS18B20 to read the peltier temperature (TEC1-12706) a DHT22 to read the room temperature and the peltier. I also have 2 fans on both ...
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3answers
243 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....
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3answers
240 views

How do I reverse-bias a resistor?

We all know that a photo diode can be used as a light detector and as a light emitter (although the way that it's built will usually make it specialized to prioritize one application over the other); ...
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1answer
48 views

Power needed to generate for heating strip - Nichrome strip element

I have a nichrome strip, about 8 mm in width - 0.25 mm in thickness - 1 m in length. I tried working around various formulas but can't seem to get a definite answer regarding how much power should i ...
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2answers
62 views

How to have a load pull more current from a low voltage high current battery

I am designing a pair of heated pants and have run into an issue with having to use batteries (or any other portable power source) to power them. What I have now is about 50ft of Teflon wire with 5Ω ...
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1answer
151 views

How does length affect current carrying capacity

Will a wire have increased current capacity if the length is sufficiently small? The reason I'm asking is that when doing PCB layout the vias often has thermal relief, which are small traces going ...
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2answers
88 views

Controlling heat gun's element: where to put SSR without disturbing motor

I'm working on a pet project of mine, creating a coffee roaster, where I'm using a heat gun as the heat source. To improve my control of the heat output of the gun, I've set up an Arduino to control a ...
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1answer
45 views

Regulators lm75xx in series : 12v to 5v [duplicate]

What do you think about puting regulators lm75xx in series in order to get less heat loss as possible : 9v-- to 5v-- to 3.3v , to get 3.3v from 12v supply? The idea is to not using a switching ...
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10answers
14k views

Why hasn't my LED burned out by now?

I have a 15 year old ReplayTV DVR. I got it used, I'm not sure when, but probably about a decade ago. It's turned on almost all the time, and it has a blue power LED on the front. The LED FAQ says ...
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1answer
126 views

LF33CV voltage regulator overheating

I'm trying to turn on a laser (3.3v - 4.5v, 100mw) using a 9v battery and LF33CV as voltage regulator(TO220 package, 3.3v output). After 20 seconds the voltage regulator is getting so much hot. I was ...
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1answer
30 views

What material characteristics are most important for heating element material selection?

I want construct a heating element by screen printing a flat coil pattern of conductive paste onto an insulated substrate. This conductive paste consists of a powder of conductive metal contained in a ...

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