Questions tagged [temperature]

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

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LM35 max input current - I have a wrong output from the sensor [closed]

I’m currently doing a small project. I’m trying to make my first pcb. That’s for a light I made. But the LM35DZ outputs a wrong voltage. My LM35 puts out 4.6V instead of 380mV. With a 12V - 2A ...
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Temperature Limits of an E ink Display?

I'm playing around with E-ink displays and I have a project in mind that would have to subject the display to extremely high temperatures (around 110 degrees Celsius). The display does not have to be ...
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2answers
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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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Can't import my .sof file to my FPGA

i am new to the whole VHDL/FPGA thing, and i am trying to import a simple AND gate to my FPGA, but i get the failed message everytime, any idea how to fix it? P.S : For some reason the device it ...
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2answers
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LM35 sensor giving weird readings [closed]

I am a mechanical engineering student and I'm quite bad at electronics so I decided to post here. For my dissertation, I require 2 circuits using the same 5.7 V DC power supply. One of the circuits is ...
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0answers
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Calculate the junction temperature of a MOSFET during pulse

Hi all I have a question regarding using a MOSFET for a constant current source. I have found this question with some answers but it wasn't clear to me yet. I want to create a constant current LED ...
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4answers
195 views

What is meant by derating in this context?

At page 33 of this motor driver there is a section includes the term derating due to temperature: What is meant by continuous current derating 4% per Kelvin in this context? Does that mean the motor ...
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2answers
133 views

Waterproofing products

does anyone know of a product that can be used for waterproofing electronics and exposed wireing that is suitable for submersion for potentially long periods? More specifically I am looking for a way ...
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Crystal compensation for temp and voltage

Introduction I'm toying with the design for a fail-safe wall clock controlled by multiple 32.768kHz crystal oscillators. I'm currently reading about compensation. Compensator from literature From ...
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1answer
124 views

PT100 - 39250 Cubic fit formula

I'm currently using a cubic fit formula I found online to derive the temperature of a PT100/385 RTD using resistance. The formula is -247.29 + 2.3992*R + 0.00063962 *R^2 + 0.0000010241 *R^3 where R is ...
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1answer
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Multimeter Giving Wrong Temperature Probe Readings [closed]

I want to ask a question about my multimeter, it's new but when i plug in the temperature cable - red to VOhm, black to COM and turn to tempreture it displays temp of period(-886°C/-900°C), and when i ...
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How to calculate resistance to use along with NTC 103 thermistor to measure temperatures between 0-100 degrees celcius

I am a complete noob to temperature measurement. I initially tried to measure temperature using LM35 but i got negative values at room temperature and the values were fluctuating a lot. I want to try ...
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1answer
404 views

Creating a temperature-dependent solar cell in LTSpice (using varistors)

I'm currently working on my master thesis and therefore need to simulate a solar cell in LTSpice. I've already modeled and simulated some examples with constant values. But for a more accurate model, ...
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3answers
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heat dissipation in watts of equipment in a box

Here is the situation, some electrical equipment will be in low ambient temperatures and I need to make it warmer so that there is no damage to it. I want to calculate how much power in watts is ...
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1answer
204 views

Faulty temperature sensor on PCB - lights keep blinking, how to replace this?

I’ve been working on a broken continuous operating high power LED system - it starts blinking when powered. This was an indication of overheating and it was clear that the cooling fans have stopped ...
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1answer
226 views

Thermopile output voltage range

I'm working with the Amphenol ZTP-101T thermopile to get IR temperature measurements and I'm confused since the thermopile voltage seems to range between -1 and 5 mV at ambient temperature of 25C (...
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2answers
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How do induction cookers measure temperature?

This is not exactly about electrical circuitry, but I hope it's close enough not to get me kicked out. Please redirect me if necessary. Almost all induction tops advertise possibility to "keep ...
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1answer
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Is there a SSR like device that can switch at kHz frequencies?

I'm designing an industrial control system that incorporates several peltier devices. As I understand it, these devices are more efficient when driven with a constant voltage, vs being cycled every ...
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1answer
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Output of LM35 temperature sensor > 3.3 V?

According to the datasheet the maximum rating of the output of an LM35 is 6 V. However, the output should give 10 mV/C and it supports upto 150 C, which results in 10 mV/C * 150 C = 1500 mV which is ...
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3answers
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Use 5v Linear Regulator and LDO 3.3V

I am designing a PCB with a STM32 microcontroller, a GPS, DataLogger and X-Bee module. The power supply is a 12V Battery. So in my project I need 5V and 3.3V, at the same time. I don't know if it is ...
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2answers
227 views

DS18B20 temperature sensor with Attiny25

I would like to make a simple thermal switch with attiny25 but first I need to read the temperature values from the ds18b20 sensor. I found some codes, here are the sources: DS18B20 lib UART lib I ...
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1answer
117 views

Which temperature transducer has these characteristics?

The resistance temperature characteristics of a temperature transducer is show in the figure below, The transducer in question is which of the following? A) Nickel RTD B) NTC thermistor C) Platinum ...
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2answers
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How to calculate the maximal temperature of a transistor

let's assume I have this transistor (IRFR640): https://www.infineon.com/dgdl/Infineon-IRFR6215-DS-v01_02-EN.pdf?fileId=5546d462533600a40153563595592114 $$R_{DS(ON)} =0,295 \Omega $$ $$V_{max} = -150V$...
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0answers
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Magnetic Field Strength Measurement at Extreme Temperatures

Hi I have just been given a project at work and we are magnetically stress testing DUTs at extreme temperatures going from -40 Degrees Celsius to 200 Degrees Celsius, I need to come up with a way that ...
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2answers
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Calculate temperature of kanthal wire per electric Watt

I'm trying to get an estimation of the temperature that a Kanthal (A1) wire would get, when applied an amount of electrical power. The wire is 30cm long. The diameter is 0.3mm (or there about). The ...
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1answer
121 views

Why do commercial components have a temperature range of -40 to 85c?

Why not -50 to 90? How was the temperature range of -40 to 85c chosen to become the industrial standard? (Some products may have a different operating temperature range, but for the majority, the ...
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2answers
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Am I misunderstanding steady state power disspation calculations?

I am looking at the Littlefuse 5KP series. It says on the datasheet: I am trying to understand how they arrive at \$P_D\$ = 8.0W. Given thermal resistances of 40°C/W or 8.0°C/W, and 100°C ...
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1answer
3k views

Calculating SMD resistor temperature rise

I am interested in knowing the actual power dissipation of an SMD resistor at a 70C ambient temperature. I am looking at a 10kOhm 2512 1Watt resitor RMCF2512JT10K0. from the electrical specifications ...
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4answers
489 views

about formula in temperature of resistor

I have 10 watt resistor. I am using resistor with ac current. I need mathematical formula for learning temperature of resistor in t time. temperature of resistor depends P=V^2/R and time. Such as ...
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1answer
223 views

Estimate temperature for silicon (p-n junction)

I need to estimate the temperature at which p-n junction made of silicon lose it rectifying characteristics. (\$N_A=N_D=10^{15}\,cm^{-3}\$) \$E_G\$ is independent of the temperature and are 1.12 eV ...
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1answer
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Temperature coefficient MOSFET vs. temperature coefficient of BJT

If you use transistors for an amplifier scheme, you want to make sure that when you parallel devices, you don't start to conduct more current if your transistors heat up. I know that when using ...
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1answer
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MAX31855 and Type K sensor seem to top down at -60°C (should be measuring -80°C)

As a prelude, I'd like to offer that I have obviously read the famous question here: Sensor for ultralow (to -85°C) freezer monitor I have set up a K-Type probe from Adafruit and their MAX ...
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1answer
4k views

How can I simulate an NTC on LTspice?

I have a schematic for a temperature controlled device which should operate at a particular temperature. For that I am using an NTC, now I have done the math by hand but it is more efficient and ...
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2answers
93 views

LSM303C temperature sensor

I'm trying to read the temperature sensor from the LSM303C. I have enabled the sensor and can see the values move when the temperature is changed. But, the format of the sensor data is not provided by ...
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2answers
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I want to attach a heat sink to the inductors on my motherboard, which glue could I use? [closed]

If I wanted to attach a heat sink to the inductors on my motherboard, which glue could I use? I have a Gigabyte A320M-S2H, this motherboard has heating problem when used with the AMD ZRyzen 7 2700X ...
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1answer
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How to calculate the Temperature rise of PCB and its surrounding air from the power PCB consumes?

I am having a difficulty understanding some mechanism regarding heat generation from an electronic PCB (Printed Circuit Board) and its effect on atmospheric temperature. I don't know if this question ...
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2answers
2k views

DHT22 bad readings on long rj45 cable

Duplicate of https://raspberrypi.stackexchange.com/questions/91781/dht22-bad-readings-on-long-cable, I figured there is chances people here have a solution for me. Hi, I'm preparing a setup with a ...
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1answer
314 views

power consumption of sensors

How to measure the power consumed by a temperature sensor theoretically? The datasheets mention the supply voltage range and output current. So, to calculate the power supply current will be used in ...
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1answer
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How to read temperature with STM32F103C8T6? [closed]

How can I read the temperature using an NTC thermistor with an STM32F103C8T6 board??
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1answer
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Conductivity formula for Metals

Is there any expression for the direct change in conductivity of metals with temperature ? I am aware of change in resistivity with temperature.
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Confusion with relating thermal resistance temperature, and electrical power and heat sinking

What is meant by the following?: In general, a device with a thermal resistance θ equal to 100°C/W will exhibit a temperature differential of 100°C for a power dissipation of 1 W, as measured ...
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3answers
286 views

How should I used two MLX90614 sensor on one Arudino Uno given that the sensor has a fixed I2C bus adress? [duplicate]

I have an arduino uno and want to use a non MLX90614. I plan to used more than one sensor on the same Arduino but I don't know how to use two MLX90614 on the same I2C bus.
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4answers
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Are circuits damaged by a constant 55°C environment?

I know that sun like temperatures kill electronics, but what about 55°C if it's constant? I have a small commercial web camera that is officially rated 0°C to 70°C. It has no jelly capacitors. I ...
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1answer
306 views

Adafruit Pt100 temperature sensor

I want to connect 3 wire pt100 sensor with arduino uno, without using any amplifier or op-amp. What could be the circuit of the same?
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2answers
1k views

STM32L4's Temperature Calculation Equation shows improper results

While using STM32L4's ADC to measure its internal temperature sensor data, I am facing an issue. The equation provided in STM32L4's reference manual, seems to showing improper results. The equation ...
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2answers
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Selecting temperature probe for home use with long cable / low power [closed]

I would like to monitor the temperature outside my home. The sensor has to be located at least 20m cable length from the display unit. Whole system should be powered by a battery (doesn't matter which)...
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1answer
112 views

Thermal drift in diodes

Hi guys and thanks for reading and your help. I can't understand a thing that my book says: "When the temperature grows, the diode will let flow more current" and then it gives 2 formulas: \$V_t = \...
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1answer
57 views

Array Resistor Temperature Coefficient

This resistor array is provided with a +/-200ppm/°C temperature drift. I understand that is the maximal allowed drift. However, does it means, within in single package array, is it likely that all ...
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1answer
55 views

Why is temperature coefficient divided by reference resistance?

In a book I am following, it is assumed that the temperature resistance relationship is linear. I would expect, then, that the resistance at a given temperature would be given by the formula $$ R_{t}...
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4answers
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STM32 MCU - Temp sensor gives weird values

I'm fooling around with a Nucleo-F103RB STM32 board and I'm trying to measure the ambient temperature using its internal sensor. I activate the ADC and get data normally via the ...

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