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

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63 views

I have three DS18B20's. I can't tell if any of them are working correctly

I have three DS18B20's (or I believe at least two of them are DS18B20's). I am currently reading them through an embedded Linux board (Raspberry Pi in this case). I have two of the sensors in a ...
1
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2answers
66 views

MOSFET Heat dissipation question

I'm designing an RGB LED strip driver, and for the MOSFETS for the PWM power switching I'm looking at using the PSMN022-30PL. It has a voltage limit of 30v, and can supply up to 30amps, which is more ...
2
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0answers
62 views

How to find replacement for a discontinued thermistor component?

I am in need of a thermistor with characteristics, such as those of now discontinued KTY84-130 (link to datasheet). I am after the exceptional linearity it features and also temperature range, up to ~ ...
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1answer
43 views

Room Temperature sense in a box

I have a sensor board placed in box with an ESP8266 and 220V to 5V adaptor board which both are considerable heat sources. But sensor is very far away from them at least 5cm. When I do not close the ...
3
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2answers
67 views

PT1000 2 wire probe. Can I add third wire?

I'v got 2 wire (81 cm) PT1000 probe which I want to utilize in a project. I would like to use current source and couple of opamps to make the measurement through ADC (uC) just like described here: ...
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0answers
30 views

how to simulate temperature PN-junction of LED in Solidworks

I am simulating one heat-sink for one LED Lamp, So i am using Solidworks for this simulating similar to this : and it works but i want to simulate temperature PN-junction of LED So have i must ...
0
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2answers
51 views

Keep a Relay ON until Switch closes

Im trying to fix an egg incubator, currently has a mercury switch (when the temperature reaches two points on the glass, the mercury completes the circuit, it has small holes and some metallic strips ...
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2answers
45 views

Burning Temperature of Copper Winding of Motor

Burning Temperature of Copper Winding of Motor. I Have 3 motors 150watt 0.75Amp 220V in Copper and Aluminum and Copper clad aluminum. I want to know the maximum internal temperature of these motors ...
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0answers
31 views

Max operating temperature for a DC-DC constant current boost converter?

I am using a GERI® Dc-dc 250w Constant Current Boost Step-up Module to convert 12V to 30-35V. It is mounted to a 100w tdp heat sink. Two questions. I know the maximum operating temperature for ...
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2answers
66 views

Sensor for very low temperature (liquid nitrogen)

I'm looking for a way to measure temperatures in range of 40 to -200 °C (100 to −320 °F). The usual DS18B20 digital thermometer works only down to -55 °C (-67 °F). A precision of 2 °C would be good ...
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3answers
42 views

Drain current as a function of temperature

I was working on the temperature dependence of the Mosfet and I obtained the following characteristics shown below. Interestingly the drain current decreases with increasing temperature. But thought ...
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5answers
917 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 ...
0
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2answers
53 views

Heatsink temperature probe

I read around that with an anonymous heatsink, you can measure its temperature when at regimen dissipating P watts. Then, (T-Tamb)/P gives its thermal resistance. Is that meaningful? Can I do this ...
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2answers
43 views

what is the base temperature when using ppm/c

I am not sure If I have phrased the question right but if not please correct me I want to know when Accuracy Parts per Million mentioned in the datasheet of voltage reference they say for example 5 ...
0
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2answers
99 views

A-Level Physics: What is the current needed to maintain the wire at a steady temperature of 387∘C?

I am stuck on answering an A Level physics question: When a current of 5.00A flows through a tungsten wire in a stream of air at 27.0∘C, the wire attains a steady temperature of 57.0∘C. It may be ...
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3answers
77 views

What is a good voltage regulator or voltage regulating circuit for my micro-USB battery charging needs? [closed]

I have a need for a voltage regulator such that I can use it to down-convert 5V USB to about 3.3V in order to charge a lithium battery. Ideally: Assuming some users may have a faulty micro USB input ...
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1answer
47 views

Design of three phase thyristor circuit for temperature controller

Circuit is powered by 3 phase, 415 V AC. This is connected to nri halogen tubes to heat a chamber up to 20 kW and 700℃. I have to control temp using delta controller DTA 7272 which will sense ...
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1answer
102 views

please help identify the temperature sensor on this PCB

The PCB is the wireless (outside) sender unit for an inside/outside thermometer. I want to create a temperature probe from this PCB so that I can measure a temperature in a very specific place. I need ...
0
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1answer
85 views

How to choose wire size for an air conditioner?

There is a difference between my calculations and what electricians say. Am I missing something? If I need to install a 3 horsepower air conditioner. Electricians always choose wires that are more ...
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2answers
115 views

How to Control the Temperature of Heating element using its resistance

In my test of a thin Film heater. I derived its Temperature coefficient of Resistance. This alpha number symbolizes the resistance change factor per degree of temperature change. My question is, Is ...
0
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0answers
81 views

Why is my snubber conducting?

I am doing some refrigeration control with arduino and lcd... and I use snubbers to keep the relays from erasing the LCD from the control... The last time I use the relay of the strip board each with ...
0
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1answer
81 views

How do modern electric blankets implement thermal sensing/feedback?

I'm looking to build my own 12VDC controller for a low voltage electric blanket (specifically, this blanket http://www.amazon.com/gp/product/B0041RQXKE ). An obvious implementation with a ...
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3answers
113 views

Can a MOSFET operate at very low temperature? [closed]

This is not a PCB question and asks only for a single MOSFET. I always wondered if there is a way that a single MOSFET would work at (any) very low temperature. I tried to find some source that ...
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2answers
45 views

PCB coating for a high temperature environment

What PCB coating is good for a high temperature environment (my environment is about 30-70 C), and is available in a spray can or so that is easy to implement without need of a device/machine?
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2answers
72 views

Fast detection of transient temperature change.. RTD? Thermistors? Thermocouples? or something else?

If I want to detect temperature changes on the order of 10ms, what is the best technology to use (besides IR)? I know Thermocouples and RTDs are pretty slow.. not sure about Thermistors.
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2answers
72 views

How to calculate a mosfet's maximum usable amperage based on a temperature

With 3.3v at the gate & 12v at the drain, how many milliAmpere can i let flow trough this mosfet keeping it at a resonable temperature? and What is a resonable temperature ? 40,60,80 or more ...
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0answers
44 views

What is the accuracy of a thermocouple after calibration?

I'd like to use a thermocouple to create a general-purpose temperature probe. However, the accuracy is quite a bit lower than I want. Almost every source I look at (example) lists the accuracy of a ...
2
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1answer
64 views

My product PC board malfunction on moderate temperature

We have been developing a product to work outdoors. During the winter months we have had no problems on our product and now in the summer the following problem came up: Our product charges in a ...
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2answers
72 views

Applying 2 x 12V to same component

The fan in my car dosen't turn on automatically anymore when the car gets too hot, but it will turn on when i switch on the A/C. So what i had in mind was to place a temperature sensor in the coolant ...
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2answers
87 views

Temperature compensation in transistor current cource

I am working with analysis of BJT current source. I didn't get the explanation of temperature compensation in NPN transistor with PNP and pull up resistor. How does it work actually?
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1answer
69 views

Rate of increase in temperaure [closed]

100 amperes pass through a copper bar of 5x5 mm cross-section. The resistivity of copper is 1.7 x 10-8 ohmmetres. Its volumetric heat capacity is 3.45 joules per kelvin per cc. Ignoring heat loss, ...
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2answers
208 views

PCB Heater design issues

I'm using copper tracks laid out on an FR4 board as a heater device. It's a serpentine design with the copper 0.3mm wide and 0.2mm spacing. I have three sets of tracks which I intend to heat up at ...
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3answers
368 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 ...
2
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1answer
23 views

Finding voltage difference in a resistance temperature device

I would like to know if I am on the right track on this question The way I approached this question is as follows. $$ R = 500[1+0.005(100-30)]\\R = 675\Omega \\$$ Then I find $$R_{eq} = 540.23 ...
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votes
1answer
66 views

Lm35 arduino and battery

I am doing a project where I need to measure temperature using lm35. I am using arduino's analog A0 to measure, I light up extra LED on an other pin while measuring. Suddenly the alarm triggers. I ...
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1answer
74 views

Electronic Temperature Control Sound Light Alarm DIY Kit - how does it work

I bought a DIY Kit off ebay (the board says www.icstation.com ICSK061A), and lo an behold, it does not work. I could not figure out what the trouble was, so i simulated it in LTSpice, but i got no ...
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1answer
45 views

How to arrange many thermal sensors in series?

Is there a kind of thermal sensor that only changes resistance if it is above 50'C and that can be wired in series? I want to wire 50 thermal sensors on 50 batteries so that i can see if any one of ...
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0answers
68 views

What components work better when they warm up? (apart from vacuum tubes)

Conventional wisdom is that heat is bad for electronics. Metals and most doped semiconductors conduct more poorly, and everything ages faster. But in my experience, some faulty appliances don't work ...
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2answers
53 views

Run multiple TECs in series or at multi-channel TEC controller?

Assume we want to drive multiple thermoelectric coolers (Peltier elements) to control the temperature of a lab setup. To accommodate for the size and shape of the device to be cooled/heated we have to ...
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1answer
50 views

High Precision Temperature reading, over a small range

I'm looking to get a very high precision temperature measurement over a somewhat small range. Ideally, I want at least a 0.001 Celsius increment, over a -5C to 5C range. Searching Digikey doesn't seem ...
0
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1answer
89 views

Relay: how to calculate the maximum current and switching current

I need some advices on a design and not values in datasheet. I know that the carry current is the current that can be supplied continuously to contacts without exceeding the maximum temperature when ...
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3answers
134 views

Converting voltage reading from temperature sensor into Celcius

I'm learning how to read temperature reading from a sensor from this tutorial. The code (Arduino) to convert from voltage reading into temperature is as follow. ...
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3answers
115 views

Calculate wire temperature [duplicate]

I have 200 mm long, 0.3 mm diameter nichrome wire. I am heating this wire with 5V AC power supply and current approximately 1.4 A. I need to calculate the exact temperature of the nichrome wire?
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0answers
33 views

DHT11 & PCB problem

I made a board which includes 220V to 5V-600mA converter(I bought as a module), DHT11 and an atmega328p. I made a measurement on breadboard and I get 45% humidity and 24 C degrees. But when I get ...
0
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2answers
86 views

How can I use electronics right below their operating temperatures? [closed]

Where I live (south of Sweden) is usually just below 0 Celsius night/day entire dark winter. I would like to set up a network in my garage which is wood and doesn't have any heating system. The ...
0
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0answers
66 views

Power enable between USB and AC/DC adapter

I have two voltage sources an USB and an AC/DC adapter 5V-24V. The adapter is connected with a diode and the USB is connected by a power path controller (LTC4412). This IC has an enable pin which ...
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0answers
25 views

Intuitive explanation about MOS threshold variation with temperature

When temperature increases, threshold voltage of NMOS for example decreases, and vice versa. I searched a lot and saw a lot of mathematical equations explaining the relationship between VTH and ...
0
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1answer
64 views

Power resistor derating

I'm going to use a power resistor which needs to dissipate around 2.5W. I will use a resistor rated at 3W. I have a thermal impedance of 88°C/W. If the ambient is at 40°C, I assume that the resistor ...
3
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2answers
509 views

Are regular fuses temperature sensitive?

Are common fuses, like AT car fuses, temperature sensitive? Say a 12v 5A fast blow fuse, would it have any significant change in its reaction at 0ºF than it would at 100ºF? In either time to blow or ...
0
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0answers
82 views

What’s the proper soldering temperature for soldering standard SMD5730 LED?

i need to Soldering a circuit board for LED SMD5730 similar to this photo: and the question is what is the best and fastest method for soldering it, what kind of tin which mark is proper and what ...