Questions tagged [temperature]

Temperature is a property of a substance related to the amount of heat energy it contains.

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105
votes
7answers
356k views

What’s the proper soldering iron temperature for standard .031" 60/40 solder?

I recently purchased a Weller WES51 soldering iron as my first temperature controlled iron and I'm looking for recommendations on the best default temperature to use when soldering. I'm using mainly ....
61
votes
11answers
34k views

Why do electronics have a low temperature limit?

Apart from condensation why do electronic components usually have a low temperature limit? For example my laptop says something along the lines of -10 °C to 75 °C temperature while in use. I can ...
43
votes
3answers
4k views

Minimum operating temperature - Outer Space?

I've been looking at some microcontrollers and I've seen they've got some "weird" minimum operating temperatures, like -25 degrees or -10 degrees etc. But I can't really understand why there is a ...
37
votes
10answers
16k views

Why is the temperature range of industrial and military products so high?

From Wikipedia the common temperature range for electrical components is: Commercial: 0 to 70 °C Industrial: -40 to 85 °C Military: -55 to 125 °C I can understand the lower part (-40°C and -55°C) ...
35
votes
10answers
21k views

Is an Arduino Uno capable of running 24/7?

I'm curious as to the reliability and durability of the Arduino Uno. Does anybody have experience in "killing" one due to excessive use? If so, how long did it take for the board to fail?
23
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1answer
3k views

Who said, “all sensors are temperature sensors, but some are better than others”?

One of my favorite electrical quotes goes something like "all sensors are temperature sensors, but some are better than others". Unfortunately, I don't remember where I read this. What is the origin ...
20
votes
4answers
78k views

Differences between thermistors and thermocouples

As I understand it, both thermistors and thermocouples are temperature sensors. So what are the advantages/disadvantages of using one over the other to measure the temperature? What are the specific ...
19
votes
4answers
2k views

How can I measure the temperature wirelessly inside a piece of meat?

For a cooking experiment, I'd like to be able to measure the temperature inside a piece of meat while it's being cooked. Due to the mechanics of the cooking process, it's going to be difficult to use ...
17
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6answers
3k views

SMT solder reflow temperature profile

I have read many website and forums about DIY reflow ovens for SMT soldering. I have also seen many solder profiles as specified by the solder manufacturers, component manufacturers, and other self-...
17
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8answers
105k views

How do I calculate the temperature rise in a copper conductor?

If I pass a current through a copper conductor, how can I calculate how hot the conductor will get? For example, if I have a 7.2kW load powered by 240VAC, the current will be 30A. If I transmit this ...
15
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2answers
6k views

Heating a wire with DC current; why is it hottest in the middle?

I am putting DC current through a wire to heat it. I would think the wire would heat up evenly but I have found that it is hotter the closer I get to the middle, or, respectively, colder the nearer to ...
14
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3answers
1k views

What kind of material of PCB should I choose to work at -40 degree centigrade?

I need to design a PCB circuit to work at (or even below) -40 degree centigrade. Normally, I use FR-4 PCB board at room temperature. However, I have learned from the question "What is the minimum ...
14
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4answers
3k views

Do computers speed up at higher temperatures?

At higher temperatures, will computers get faster? Evidently, one always wants cool a computer down as higher temperatures can damage core components. However, is it an interplay between silicon, ...
14
votes
2answers
1k views

Is it proper to use an internal layer as a heat bed if I want to warm my multilayer PCB?

I need to design a circuit to warm my PCB. There are many ways to build up such circuit. But I learned from a post "Warming PCB in a low temperature environment" that maybe I can use traces as heater. ...
13
votes
7answers
4k views

Cheap temperature sensing with MCU

I am looking for a cheap solution for sensing temperature with a MCU. My requirements are: 2 channels temp range: 30-35°C temp resolution: 1-2 K cable distance (MCU -> sensor) 10cm - 2m are ...
13
votes
4answers
6k views

Why do temperature-voltage curves of all thermocouple types pass through the origin?

Notice that the temperature in the graph is in °C, not even in °K. 0°C is the border between temperatures of water and ice under 1 atm pressure. Why do thermocouples give 0V voltage at a temperature ...
13
votes
3answers
10k views

Can an infrared thermometer (IR gun) be used to measure the ambient room temperature?

I know the principle of an IR thermometer, but have one question regarding that are as below. As an IR thermometer senses the radiated IR waves from external bodies coming in their field of view and ...
13
votes
3answers
4k views

What prevents semiconductors working below -40°C or so?

Most devices seem to be characterised over -40°C to ≥85°C. What limits them to cold temperatures? Can an IC be damaged by keeping it too cold? Does this apply to other devices, e.g. diodes, ...
13
votes
2answers
3k views

Warming PCB in a low temperature environment

I have to develop a microcontroller circuit that will run at low temperatures (as low as -60C). I want to heat the FR4 PCB board until it reaches the commercial temperature range above -40C. I found ...
13
votes
3answers
21k views

Do MOSFETs usually burn open or closed?

I was wondering if a power MOSFET fails due to overheating, will it usually burn as an open-circuit or short-circuit? Also, does over-temp damage usually cause the gate oxide to blow through as a low ...
13
votes
4answers
13k views

What is the minimum temperature for FR-4 PCBs?

My company is working on developing a product that will go into commercial freezers, so my boss asked me to provide operating temperature specifications for the product. I can find "operating range" ...
12
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4answers
3k views

What mad solder type is used for BGA?

Having nothing to do in my workshop, I decided to practise my skills a bit. I digged up a scrapped graphics card from the junk box and decided to try to desolder the RAM-chips (BGA) after seeing how "...
12
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5answers
7k views

Can I improve the accuracy of LM35 temperature sensors by averaging several sensors?

Can I create one super-sensor by averaging together the readings from several LM35 sensors? Wouldn't this be more accurate because I'd be averaging out the systematic bias in the individual sensors? ...
12
votes
7answers
5k views

wireless temperature sensor [closed]

Are there any low-cost (<50$USD) wireless ambient temperature sensors available? I would like a simple to interface to the sensor i.e. IP over Wifi if at all possible.
12
votes
2answers
4k views

Controlling an RGB LED color range from an analog temperature sensor (no Arduino, etc.)

I'd like to combine an analog temperature sensor with an RGB LED so that I get a range of colors based on temperature. Low temperature blue, high temperature red, with color fade between them as the ...
12
votes
2answers
314 views

What is reasoning behind the common wisdom of limiting the temperature rise of a PCB trace to 5/10/20°C?

When deciding on the trace thickness required to carry a certain amount of current on a PCB, the answer depends on how much temperature rise you are willing to accept. This leads the designer into the ...
11
votes
4answers
4k views

What exactly gets “worn out” and damaged by heat?

It's quite common knowledge that heat is bad for electronics. That constantly high temperature decreases the expected lifetime of computer parts even if they are not overheating per se. If, for ...
11
votes
5answers
2k views

Electronics in high temperature - operating 30 mins - 2 hours, up to 500 °F - possible?

Would electronics survive if the ambient temperature of the environment was between 120 °C (250 °F) and 260 °C (500 °F) and the operating time was between 30 minutes and 2 ...
11
votes
5answers
1k views

Reliability of DS18x20 temperature sensors

I'm using Maxim's DS18x20 (I've actually got more than one variant) 1-Wire temperature sensors to log the temperatures in various rooms in my house once a minute. About one reading in a thousand, I ...
10
votes
6answers
4k views

Sensor for ultralow (to -85°C) freezer monitor

I am planning to build a series of Arduino-controlled temperature-reporting units for a room full of "Ultracold" -80°C freezers. (I ultimately want to convert the signal to a serial stream that will ...
10
votes
3answers
991 views

P-Channel MOSFET Inrush Current Limiting - Transistor burn issue

I'm fighting with PFET inrush current limiting circuit discussed here: P-Channel MOSFET Inrush Current Limiting In my circuit is input voltage 24V DC and C_Load is 6mF. I'm switching on transistor ...
10
votes
3answers
2k views

Need for Temperature Compensation of Current Mirror

I am currently learning about current mirror configurations. I have made two of them so far. Both of them worked as desired but, when heated or cooled, the current through the right side (the side ...
10
votes
5answers
7k views

Accurately measuring temperature with Arduino

I'm trying to build thermostat with Arduino. I want to power it using mobile phone battery/charger which makes system voltage quite variable. Right now I use Arduino Uno, but once it is complete I ...
10
votes
3answers
698 views

Best humidity/temperature sensor for a nappy?

Special needs kids have big troubles with potty training. A 'wee-wee' alarm would be of a lot of help. What would be a good way of detecting 'it' without electrocuting anybody? A possibility would be ...
10
votes
1answer
2k views

MOSFET power dissipation calculations - Diodes Inc. datasheets

Looking at Diodes Inc. datasheets, I am having trouble following their power dissipation limit calculations for their MOSFETS. E.g. for DMG4496SSS http://www.diodes.com/_files/datasheets/ds32048.pdf ...
9
votes
4answers
1k views

Is it possible to have a MCU work at -55 degree, with specification of -40 to 85 degree working environment?

I heard that someone mentioned the method of screening: to have 10 MCUs working at -55 degree, and find out the ones which can work properly, throwing the broken ones away. Is the method applicable? ...
9
votes
3answers
2k views

Please explain in layman's terms how a PID accounts for inertia in temperature control

I'm building my own hobbyist microprocessor-controlled reflow oven. I'm using (mechanical) relays to turn the heaters (i.e. quartz tubes) on or off. I've noticed heating lags a couple of seconds ...
9
votes
1answer
1k views

How does soldering affect the internal bonding between the IC die and its package?

In other words, How does the IC fabricator solder these thin wires between the die and the pads and guarantee that the soldering iron temp (300C for example) on the IC pads won't desolder them?
9
votes
3answers
2k views

How to tune a PID controller to a nonlinear process

I have a nonlinear thermal process (nonlinear radiation becomes more and more present as temperature goes up) that I would like to tune a PID controller to. I'd like to control the temperature as ...
9
votes
4answers
3k views

How to cool electronics when the air is always hot

I'm in the process of planning an experiment that involves placing some electrical equipment in a mine for a year or more. Where the equipment will be placed in the mine (770m in depth,) the amient ...
9
votes
3answers
5k views

Op Amp circuit not behaving as desired

Found a circuit on the net that should do exactily what I want (control a cooling fan) but it is 'on' all the time. Not sure if there is an error with the schematic or if there is something else I've ...
9
votes
1answer
2k views

Freezing DRAM for forensics (coldboot)

I've known about the coldboot trick for a while, but have never really considered the physics behind it. I've read the paper, but it doesn't really cover why it works. How does physically cooling a ...
9
votes
2answers
5k views

Max operating temp of IC's

Why do so many IC's have a max temp range of 125C? Is it due to packaging material tolerances, ie the black plastic enclosures and/or the bonding epoxy that holds the die to the package and/or ...
8
votes
4answers
4k views

Storing batteries in a refrigerator

The electro-chemical reaction is more favorable at higher temperatures. Consequently, when it is warmer, the batteries will perform better. This is also evident from practice: old batteries do not ...
8
votes
5answers
10k views

Measuring temperature with ±0.01°C accuracy

What is the most accurate way to measure temperature to ±0.01 °C? I have looked into using a Wheatstone bridge (with a minipot for minor calibrations) and an RTD for its precision and range. I ...
8
votes
3answers
3k views

MSP430 serial communication failing in cold weather

I have a product using the MSP430 microprocessor, which has been selling for a couple years now. One of the MSP430's jobs is to communicate over async serial to a low-power radio. With the onset of ...
8
votes
2answers
3k views

Selecting bias resistor for thermistor

Rt is thermistor. Rb is bias resistor, which value I need to calculate. The temperature that I'm interested in is giving ...
8
votes
5answers
6k views

Temperature sensors for an Arduino sous-vide project

I'm creating a PID controller for sous-vide, like this one, and am trying to decide which temperature sensor to get. Priorities: Cost: < £25 delivered in the UK Accuracy: +/- 0.5C Range: 0 - 100C ...
8
votes
5answers
3k views

How to best connect a temperature sensor to an aluminum block?

2 questions: How would you connect a temperature sensor to an aluminum block? Could I use a thermal adhesive, basically just gluing the sensor to the block? Which sensor would you buy? I like the ...
8
votes
2answers
10k views

Using 1N4148 As A Temperature Sensor

Can I know which component senses heat or acts as heat sensor in the following circuit? In the given diagram, it is said that the 1N4148 diode acts as the sensor. But basically it is a zener diode and ...

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