Questions tagged [temperature]

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

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408 views

Can anyone identify this thermometer probe?

I've tried to use this probe to detect temperature from an arduino microcontroller. Unfortunately, I can't seem to get a decent reading out of this. I need to know appropriate coefficients for ...
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3answers
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What is the I2C ACK, and how do I detect it?

I am writing an FPGA driver in Verilog for a temperature sensor (datasheet available here). The communication protocol is SMBus, a close cousin of I2C. Now reading the datasheet, I understand that the ...
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Dealing with bidirectional communication over 1 pin

I am writing a Verilog driver for a simple temperature sensor connected to an FPGA. (The temperature sensor datasheet is available here.) Communications occur over one pin, the ...
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4answers
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Trying to get the 8bit to 10bit ADC Conversion formula right for Arduino with Temperature probe

I have an Arduino Diecimila and a bunch of old Phidgets 1114 Temperature Sensors. I want to be able to get a somewhat steady / accurate temperature from these sensors inside my arduino sketches. The ...
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1answer
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ROV (underwater) temperature sensor design considerations

I'm the 'technician' for a SeaPerch ROV team (since I know the most about electronics) and I need an underwater temperature sensor able to mount on a ROV. Since I don't have much experience with ...
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1answer
369 views

Does the Maxim DS18S20 stop converting temperature if a reset is sent during the conversion?

I have a couple of devices on a 1-Wire network including a DS18S20. If I start a temperature conversion, it takes 750ms for it to complete. During that time, I would like to query other devices on ...
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3answers
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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 ...
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Have I cooked my caps?

Recently been calibrating my solder reflow oven to work with a higher temperature solder paste. Had a few boards come out that were slightly over done. At 250 degrees Celsius I noticed that the silk ...
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3answers
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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 ...
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1answer
169 views

Diode survivability at 260°C

I have an idea for a project, which needs to be able to measure temperatures up to 260°C. The accuracy is not crucial (±5°C is fine) but it is important that it can measure lower temperatures too. I ...
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4answers
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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 ...
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How hot can electronics get?

How hot can my mouse get before it stops working? Assume the plastic is removed so it doesn't melt. I'm really trying to gauge the max operating temperature for electronics that have no moving parts (...
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What happens when reaching the max temperature on a temperature sensor?

I need to monitor the temperature of a hot plate so it stays at 210C I am just using a Arduino and lcd to display the temp using a DS18S20 (I have it ready but not actually using it to measure the ...
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5answers
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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? ...
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2answers
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Temperature-Controlled Fan

How do I trigger a fans function after a setpoint temperature is reached? I want to avoid using a PID Controller, and my heating element will be external of the circuit. Once the fan cools the ...
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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 ...
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2answers
288 views

What rechargeable battery is suitable for severe frost (−10 Celsius and below)?

Suppose I want a rechargeable battery for a hybrid electric vehicle like Toyota Prius - one that can power the vehicle traction motor at low speeds. The vehicle would have to operate in a region where ...
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4answers
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Operation of infinite switch

Many electric stovetops are operated by an infinite switch, which pulses the current on and off for intervals determined by the dial setting. The actual control is effected via a bi-metal switch that ...
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5answers
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Temperature logging setup for refrigerator

I've been having some issues with my refrigerator lately, and so I've been imagining some kind of temperature logging system. I want it to log the temperature every 5(?) seconds, door open/close ...
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2answers
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How does temperature affect wireless transmission?

I'm working with Xbee Pro with wire antenna to transmit data from inside a refrigerator. The receptor outside is the Xbee with RPSMA antenna. I use an extern MCU to control the data transmission, ...
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3answers
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Can capacitors be exposed to temperatures above the max. operating temp?

I have an NVIDIA GeForce 7300LE graphics card that's having problems (see here), and I heard about baking the card to restore old solder joints. The thing is, this involves putting the card in the ...
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4answers
3k views

Alternative to NTC Thermistor

I am designing a system which turns on at 45 degC. I want to place a device in series with my circuit that ideally has infinite resistance below 45 degC and then 0 resistance above 45 degC. I guess ...
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2answers
602 views

Reading back 0xffff for temperature from I2C BMP085 temp/pressure sensor

I'm interfacing a Rabbit 5760 CPU to a Bosch BMP085 sensor via I2C. Everything is fine except reading the temperature register is reading back 0xffff (see BP_FINISHTEMP case in switch). I can't see ...
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6answers
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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-...
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2answers
1k views

Why LM35DZ temperature sensor accuracy deteriorates towards the lower end of the range?

I get some curious data from my LM35DZ temperature sensor. Every minute or so I take 8 measurements 1/2-second apart and average them. The graph below shows that the accuracy of the measurements ...
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3answers
1k views

Battery for reliable field sensor with low temperature conditions

I'm designing a frost alarm for farmers. The basic idea is that the farmer puts a sensor somewhere in his field. This sensor reports the temperature every 10 minutes to a base station with a wireless ...
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2answers
3k views

I2C - Cannot read temperature from TC74 with PIC16F887

The question was: I want to read temperature from TC74 using I2C module of PIC16F887, however, in Proteus simulation, I see noises in I2C Debugger Tool's output. ...
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4answers
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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 ...
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3answers
1k views

Getting temperature data from traditional pizza oven

I'm building a traditional Italian pizza oven in the back garden and would like to get some temperature data back to my home computer. The major requirements for such a piece of kit are: Record a ...
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1answer
4k views

Why higher temperatures shorten the lifespan of a PC component?

It is usually advised to keep the temperatures low for every component of a PC. Not only there is a fan (or similar system) for the CPU or GPU, but there are optional fans for RAM, or hard disks. ...
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2answers
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What causes the increased power consumption of a window air conditioner in the afternoon?

I installed a new 8000 BTU window mount air conditioner on the weekend on a wall that is west facing. I plugged it into a Kill-A-Watt to monitor its power consumption and noticed in the morning, when ...
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5answers
4k views

Low PPM Tc Resistors for Voltage Divider circuit?

I have a voltage divider circuit that cuts an input voltage in half. The half voltage is fed into an ADC. I need this reading to be stable over temperature. The resistors are 100K, but I don't ...
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4answers
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LM35 Temp Sensor Distance Issue

I recently bought a LM35 Linear Temperature Sensor off littlebirdelectronics.com (as well as other Arduino stuff) and everything all worked fine when I had the temperature sensor attached up to the ...
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1answer
11k views

Diode Temperature effect

How will temperature affect the output of a semiconductor diode?
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1answer
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NS9750 operating temperatures

I have a ticketing device with an ARM9 CPU, more specifically a NS9750 module. In the datasheet, its operating grades/ambient temperatures are listed as follows: 125 MHz: 0 to 70ºC 162 MHz: -40 to +...
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2answers
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how to calibrate temperature sensor IC DS1621?

I have made temperature indicator using microcontroller P89V51. My temperature sensing IC is DS1621. I'm using LCD for the display..n ckt is working very fine, Do I have to calibrate this IC? If yes, ...
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3answers
3k views

Using K-type thermocouple to measure human body temperature

Is there anything I need to he aware of when using K-type thermocouples? I got the idea by touching the probe. I can get a reading when measuring temperature for 30 seconds using a DMM. A commercial ...
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6answers
4k views

Temperature sensor for Linux [closed]

I'm looking for a temperature sensor, that can be connected to a computer over an interface that is ubiquitous, like USB. I'd like to read the temperature data over the command line. Any suggestions ...
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3answers
685 views

Regulator cooling in a confined space

I've designed a simple PWM RGB LED slow fader to be used as a garden lighting effect. My circuit works great, but I under-estimated the amount of heat that is generated by the 7805 linear regulator. ...
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1answer
3k views

How do I measure a PT100/1000 with a Arduino over I2C?

How do I measure one or more PT100/1000 (PTC Resistor) with a Arduino/ATmega328 over I2C? Are there any ready microchips? Do I need to construct my own circuit? If so, are there any ready schematics?
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LM317 getting hot

Should an LM317 (specifically a TI LM317MQDCYR) rated for 500ma output current really be getting hot to touch when only pulling 170ma at 5V? Package is SOT-223, input is 9V. Is this normal?
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2answers
604 views

Any issues with using an opamp as a constant current source for temperature sensing?

I understand that most people use a bridge circuit for RTD and possibly thermistor temperature sensing. I'm trying not to do that for several reasons. I'd like to use an opamp in the classic ...
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4answers
19k views

How to calibrate a temperature sensor

I am using an LM35 temperature sensor, which produces an output of 10.0 mV/°C. My circuit will handle temperatures up to around 90C What can I do to check the LM35 output, and maybe fine tune it for ...
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1answer
187 views

Measuring temperature of microcontroller and other large ICs

I'm going to be using a microcontroller and SDRAM IC in an enclosure that could, given some environmental variables that I have no control or knowledge of, get too hot for the devices to work properly....
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2answers
794 views

More Options for Reading Thermocouple Signals

I've tried a few options for reading the signals from thermocouples over the years. The cheapest way (component cost) is likely to be DIY, and a lot of work involving lots of analogue stuff that I'm ...
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7answers
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Building a temperature-controlled water bath

I want to build an accurate (±2 °C) water heater (sous vide) that heats water somewhere between 30-100 °C according to user input. Although I have an engineering background I have no ...
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3answers
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What is 'best' temperature sensor for an array of sensors

I'm looking to make an array of sensors to record the temperatures in a house at various points eg. Above flat metal roof, inside flat roof cavity (above 1st floor), ceiling of room (1st ...
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6answers
729 views

Cheap way of temperature testing my boards

I want to make sure my product will work over a large temperature range of -40C to +75C. I can verify on the low end down to about -18C using a household freezer (which is probably good enough) but I'...
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3answers
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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 ...
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2answers
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Is there any reasoning behind making capacitors go to 105°C?

Electrolytic capacitors are often rated -40°C to +105°C. I've always wondered about the extra 5°C. This also seems to be the temperature range for some types of microcontrollers, and is marketed as an ...