Questions tagged [temperature]

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

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60 views

analog values to ppm

How to transform a set of analog voltages from V to ppm/K? I have to use this to calculate the temperature coefficient of a bandgap. Is the derivative the same as the temperature coefficient ...
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What could be the reason that this transistor gets too hot unexpectedly?

In the following circuit, for the transistor it can be calculated that: Vce=4.5V and Ic=170mA. I also implemented this on breadboard and measured almost the same quantities. The opamp is an LM324 and ...
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I need to measure a new temperature device called and ICTD but no meter exists, can I make one with an FET Circuit?

I need to measure a new temperature device called an ICTD but no meter exists, can I make one with an FET Circuit? This device scales a variable microamp signal of .000233 amps DC at -40C to .000375 ...
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0answers
35 views

Will the resistance of the certain valued resistor decrease or increase at cryogenic temperature?

I tried to measure resistance of 332k Ω while dipping in liquid Nitrogen (cryogenic temperature) I got the resistance value near about 458k Ω, doesn't it contradicting "Resistance should increase and ...
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0answers
42 views

Why does my MAX30105 give wrong temperature reading?

I am using a custom made board for the MAX30105 sensor. I am checking with ESP8266 Arduino (Sparkfun max301505 library.) When the sensor is on, the temperature reading is 10 Celcius. It ...
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1answer
44 views

Controlled Temperature Coefficient of chip resistor

I am designing and experimenting with current source circuit using Op amp and transistor. As output current increases, the temperature rises which then makes the output current value to change for ...
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1answer
46 views

STM32L0x1 incorrect temperature reading

I'm having trouble reading the temperature, its values are incorrect. The temperature in the room is 22C and the temperature of the sensor shows 55C (selfheating and the measurement error cannot be ...
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1answer
79 views

What temperature should I expect by lighting 3W-LEDs?

I have a PCB with 10 LEDs (reference : SPHWH2L3D30ED4TPK3) which will each dissipate 3 W (forward voltage of 3 V and 1 A passing through). The PCB is a circle with a diameter of 20 cm and LEDs are ...
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1answer
47 views

1V voltage reference and temperature coefficient

There are precision 1V voltage references like ADR510 which I don't have access to, though I do have LM385 1.2V, LM336Z5 5V and the famous TL431 at hand. The easiest solution is to use a voltage ...
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1answer
40 views

Thermistor - NTC 10 D-9 , steinhart-hart equation

I have the steinhart equation which is 1/T = A + Bln(R) + C(ln(R))^3 Where can I find an exact datasheet for NTC 10 D-9 ,(Please attach the exact datasheet with its temperature and resistance table ...
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3answers
79 views

Current from thermocouple (T/C)

Studying thermocouples (T/C), I have a question regarding the output. Generally speaking, in the case of T/C, we measure the thermoelectric voltage in millivolts. Why do we calculate not current, but ...
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1answer
30 views

temperature stability in current mirrors

I have read here that temperature stability is one of the performance issues in current mirrors. Can anyone what does temperature stability mean in current mirrors? Thanks.
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Board is getting reset when I lower the temperature in Thermal Chamber

I have a board which I put in the thermal chamber. I increase the temperature inside the thermal chamber to 85degC. Soak it for 2 hours and note some readings. Then, when I change the temperature to ...
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2answers
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Mosfet Temperature Rise: IRF4110 with 10% Duty Cycle Square Wave

So I have this MOSFET: IRF4110 I am switching on for 2ms and off for 18ms (Making it a 50Hz 10% Duty Cycle) and current in on time is 100A at 10V. So the datasheet says 4.5mohm and thus I calculate ...
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0answers
40 views

Calculating resistor's temperature at equilibrium

I'm trying to characterise a resistor's temperature at equilibrium when I know the voltage on it and the ambient temperature. I have a few ways to measure but I get mixed results, so I'm searching for ...
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3answers
894 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 ...
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0answers
57 views

Multiple temperature sensors - One output

I'm a plumber and I'm not able to find a commercial product that fits my needs, so I'm wondering if it would be feasible to build it from scratch... I'm familiar with basic understanding of electronic ...
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1answer
50 views

Does changing the diameter of a wire affect the TCR of a wire?

I have a wire wound resistor that is changing too much when being heated and cooled. I know changing the chemical composition of the wire is the biggest factor in changing the temperature coefficient ...
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1answer
48 views

Temperature sensor for solar dryer heat control

I am designing a control system that runs a fan and electric heater based on the temperature measured inside of a hybrid electrical/solar dryer (for fruits and vegetables). Temperatures inside could ...
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1answer
50 views

Where to measure ambient temperature limit inside of an enclosre?

In a project, we are to place several components inside of an enclosure. Some of these components are to be considered safety critical, and their specified operating conditions must not be exceeded. ...
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1answer
102 views

What is the effect on lithium ion batteries from long term storage in sub-freezing temperatures?

I am designing an off-grid power system for a mountain cabin that is not used in the winter. The ambient temperature can get as low as -20deg F (-29deg C) during the winter. Due to snow and other ...
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1answer
51 views

Why is there a big difference between the temperature parameters of these regulators with the same name?

I have two datasheets for the same TL780–05C regulator one from Texas Instruments and another from MOTOROLA. I'm looking at the data for the TO-220 packages. I need to estimate the total junction ...
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1answer
29 views

How to use a power meter to measure irradiance?

I have got a Zes Zimmer LMG95 power meter and an RS-ID-5 Fraunhofer ISE WPVS reference cell. The LMG95 has got simultaneous voltage and current measurement and can do custom calculations. The WPVS ...
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1answer
41 views

Temperature and flash corruption in microcontrollers

I'm repairing quite the pricey device, where a strain gauge failed. It's a pressurized device, and the strain gauge measures the internal pressure by means of it. The crux of the matter is that the ...
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1answer
33 views

Function of temperature compensation (Tcm / tCom) Pin of MG811 CO2 sensor

I have the MG811 CO2 sensor and can use it in genrell. But for me the function of the temperature compensation (Pin "Tcm / tCom") is not quite understandable. Here is the circuit of the sensor: ...
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2answers
55 views

High temperature reading of mechanically-separated body

I have a device with 2 mechanical parts. One side is stationary and can be connected to an electronic circuit with power. The second side is an enclosure that can have high ambient temperature (100-...
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0answers
31 views

Temperature coefficient of a voltage source

Is the temperature coefficient of a voltage source related to the internal resistance of the voltage source? Why does the voltage increase/decrease when the temperature is increased or decreased? In ...
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3answers
1k views

ppm/K to ppm/°C formula

How can I transform the variation over temperature: 25 ppm/K to ppm/°C? I was searching for the formula and all I could find was that 100 ppm/K = 100 ppm/°C. Is this true?
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1answer
63 views

Is the parasite mode of a DS18B20 less power consuming than the normal mode?

Description I'm trying to make a few small temperature sensors for in our house and want to go for "low powered battery operation". My current plan is to use esp-now in the esp8266, deepsleep ...
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2answers
65 views

Alkaline battery performance at -30 Celsius

I am making an IoT project and planning to power it with alkaline batteries. Their safety and low cost are really appealing. Their low discharge capability is not a problem. The batteries need to be ...
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2answers
70 views

How to efficiently mux many signals to/from a climate chamber?

I am building a setup to measure various parameters across a temperature range from -55°C to +125°C. The devices under test will be placed in a climate chamber. There are around 10 signals from each ...
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1answer
65 views

What can happen to a relay at temperature outside of its spec?

I am building a system for measuring some parameters in a climate chamber. The test runs from -55 to +125°C. I need to switch some signals between multiple devices under test using relays. I want to ...
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0answers
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Is this circuit ok for MCP9700 temp sensor?

I am trying to use multiple MCP9700 temperature sensors and probe certain power IC heatsinks for sensing the temperature through an attiny85. I have two parts in the overall schematic. For each ...
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1answer
87 views

MLX90632 eeprom write problem

I am using an MLX90632 (MLX90632-S-LD-BCB-000) infrared temperature sensor to build an application which reads an object's temperature among other things. MLX90632 manual The MLX90632 comes with a ...
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1answer
35 views

Read Data from Temperature Controller using MATLAB, Need Help

I am trying to read data from a temperature controller called ATR-401 using MATLAB's tool box called Instrument Control Toolbox but every time i try to read data from it i get an error "A timeout ...
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2answers
339 views

Very high temperature (>500C) IC packages

I was looking for IC packages where I can mount a small wafer (3mmx3mm) wire bond to the leads of the package and conduct operation at 500C. I have contacted couple of companies which do ceramic IC ...
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0answers
23 views

Smart High and Low Side Mosfet

For example I have two smart high or low side mosfet that have 4 channel. One high side driver has 1 amper per channel. Other high side has 2 amper per channel. I tested these smart high side mosfet ...
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0answers
92 views

ATMega328P - DS18B20 temperature sensor returns incorrect temperature values

I'm using a Dallas DS18B20 sensor to measure temperature in conjunction with an AVR ATMega328P microcontroller (using this AVR C library to implement the code). Unfortunately, the value always returns ...
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2answers
93 views

How can I decide relay on-off periods depending on the PID output [closed]

In my PID project, I am using discrete time PID formula as follows. u(k)=u(k-1)+Kc * [(e(k) – e(k-1)) + (Ts*e(k))/Ti + Td/Ts * (e(k) – 2*e(k-1) + e(k-2)) As you know PID output increases over time ...
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0answers
174 views

STM32H7 on-chip temperature sensor reading stable on 'Y' revision, but unstable on 'V' revision chip

using the STM32H753VIT6, I like to monitor the on-chip temperature sensor. The environmental temperature can become about 50 degrees Celsius, and the board is housed is a small plastic (DIN-rail) ...
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2answers
383 views

Which one of these DS18B20 temperature sensors is fake?

A while back I bought two DS18B20 for half price, and today I bought another one for double the price. The part number on the cheaper one is printed while on the expensive one it's laser etched: On ...
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1answer
94 views

How to calculate temperature in Wire?

Let's say I have 1m of 2,5mm² copper wire, insulated with H07V-K. The wire carries 40A and environment temperature is 25°C. The wire is suspended in free air. How hot will the wire get? And how can I ...
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1answer
46 views

Relay coil inductance variations vs. temperature

How does relay (something like this https://www.hobbytronics.co.uk/datasheets/songle-12v-relay.pdf) coil inductance changes with increasing/decreasing temperature? And how can we calculate the new ...
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0answers
70 views

Temperature vs. lifespan: the 10 degrees Celsius 'rule'

TL;DR: What's the origin of the 10 degrees Celsius rule? I have heard many times that for every 10 degrees Celsius, the lifespan of components gets halved. There are many documents on the web quoting ...
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3answers
135 views

How to turn on LED with temperature sensor

I'm new to electronics and I want to control a device using a temperature as an input. Right now I saw this video on youtube and want to follow it as well as know what the components are for. https:/...
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1answer
51 views

Connecting K-Type Thermocouple wires to a data logger with a male and female plug

I'm trying to setup a temperature data logger using Graphtec GL240. I will be using K-type thermocouples for the logger. I want to run short length of k type cables from the logger to a female K type ...
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3answers
55 views

Need help in cable temperature calculations

I am trying to calculate how hot will a 0.6m long 28AWG wire carrying a load of 12VDC, 0.2A get. I understand that are other factors such as environment cooling rate, thermal resistance between air ...
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1answer
68 views

How bad are 3 degrees Celsius for a lithium battery and electronics?

I have a PCB powered by a lithium battery , it works well inside the house, but when I leave it exposed to low temperatures with humidity the PCB or the battery stops working. I leave the PCB in the ...
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0answers
40 views

How to convert a temperature readout to a K-type thermocouple voltage? (reverse thermocouple converter)

I am working with a commercial heating controller device which takes in a thermocouple input in order to regulate the heating temperature. However, in some cases, the thermocouple junction just isn't ...
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1answer
42 views

DIP temperature Sensor with serial port [closed]

I am looking for a temperature sensor which is in for of DIP suitable for breadboards and serial communication that is usable for Arduino. I am not after a resistive or an analogue sensor. I am not ...

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