# Tagged Questions

A thermocouple is formed by a contact of two (2) dissimilar conductors. The voltage across thermocouple is governed by Seebeck effect. Thermocouples are widely used as temperature sensors.

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### Calculating thermocouple voltage error due to ADC anti-aliasing filter resistors

I am designing a circuit to read thermocouple output using an ADC (AD7124-8). I am using the following circuit with 3K ohm resistors for ADC anti-aliasing filter: I am trying to calculate the ...
236 views

### How to choose ADC Anti-aliasing filter cut-off frequency in thermocouple readings?

I am reading a thermocouple in an industrial environment. Thermocouple output is read twice a second. ADC performs 50/60 Hz filtering internally. I had the intention of using a filter with a cutoff ...
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### Why are the junctions where ADC pins connect to PCB board ignored in thermocouple cold jucntion conmpensation calcutaions?

Why are the junctions where ADC pins connect to PCB tracks ignored in thermocouple cold junction calculations?
357 views

### What is the main source of variation between thermocouples of the same type

Thermocouples have stated tolerances [wikipedia]. However, the characteristic behaviour is defined by the materials in contact, so there aren't size or shape considerations as for RTDs. What are the ...
92 views

### How does a thermoelectric generator generates electricity? [closed]

I want to know how a thermoelectric generator generates electricity. I know that it converts 'heat flow' to electricity.But some people say it consumes heat and converts it into electricity.The rest ...
108 views

### Thermocouple Op-Amp - Arduino

First of all, I know that this is not the best way to do this, even more so because I am using the LM358. I don t want extraordinary results. Now, on the matter of the problem. I have attached the ...
46 views

### TYPE-K Thermocouple wire to a thermistor

I have thermocouples and thermistors on my job measuring temps. I accidently ran type k thermocouple wire to my thermistors. I am wondering if they will still read accurately or if I need to replace ...
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### Is my K-type thermocouple defective, or am I using it wrong?

I have two K-type thermocouples that look exactly like the one below. One was sold as good to 800C, and the other was quoted as having a temperature range from 0-400C. I have been swapping them ...
195 views

### Using a type K thermocouple ADC to measure a type E probe

I'm currently trying to measure the temperature of an off-the-shelf soldering iron. After realizing that the temperature-sensor in the soldering iron is a thermocouple, i ordered a type-K thermocouple ...
110 views

### Multiplexing thermocouples, what to look for in multiplexers?

I would like to use a MAX31855K IC for amplifying K type thermocouple response. This alone seems rather straightforward, but I'm also considering connecting 2 or 3 thermocouples to one IC. I don't ...
183 views

### Problems with op amp thermocouple circuit

I am trying to use an LM358 to amplify a thermocouple and read in the resulting voltage into an Arduino. I bought an Amico thermocouple from Amazon: http://www.amazon.com/Probe-Thermocouple-Sensor-...
171 views

### DAQ Thermocouples type K + LabView

I hear that thermocouples, especially type K, got really low output voltage ( 41µV/°C. ) Someone told me that if I had 16 bit DAQ device I would need a range from - 1 V to 1V to measure 1 °C. So ...
92 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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### 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 ...
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### 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 ...
283 views

### Strange output from an AD595 in single supply mode

device under test I've got a K-type thermocouple wired up through an AD595AQ to an Arduino in single-supply mode (12VDC to pin 11), with the addition of an RC filter across the thermocouple inputs (...
263 views

### LM324 instead of LTC6081 for thermocouple

I have circuit schematic with LTC6081 for thermocouple, but LTC6081 isn't available in my country. Can I use LM324 instead of LTC6081?
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### Thermocouples - Understanding signal vs. power grounds

I have a simple circuit that reads a temperature and toggles a valve. The thermocouple functions when the dotted ground wire is unplugged, but fails otherwise. Minor edit: The 3.3V going into the ...
186 views

### Understanding slow response of multiplexed thermocouples

I have a simple circuit swapping eight thermocouples through a MAX31855 analog-temperature-to-digital converter with two CD74HC4067 multiplexers. The MAX31855 is wired to the SPI pins on a raspberry ...
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### temperature loss in a metal surface

A metal cone is heated at certain temperature . say 45 -50 deg C. i placed a thermocouple(k type) over the surface of the metal to measure the heat transferred over the metal surface. The ...
130 views

### Welding Thermocouple to Test Sample

I have a 3mm copper test sample that is going to get heated up, and I would like to know how hot it is actually getting. Previously, we have just held the thermocouple close to the sample, but we are ...
835 views

### The Op-Amps don't work correctly for this circuit [Thermocouple]

I'm trying to connect a thermocouple to an Op-Amp to amplify the output of a thermocouple. this is the circuit: Also for R17 I put a 5k09 resistor instead of 6k8 and for R18, 1k032 and for R19, ...
340 views

### Analog Sensor of 0 to 10 v connection to BeagleBone Black

I have an analog sensor(Thermocouple) which provides an output voltage range of 0 to 10 volt. I want to connect it with a Beagle Bone Black. BBB accepts 0 to 1.8 volt as analog input. I thought of ...
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### Thermocouple temperatures change drastically when my whole system is powered vs when just my arduino is powered

I apologize in advance if this should instead go in the Arduino stack exchange, but I feel it should be here. I'm using this thermocouple / amplifier pair with my Arduino Uno. I am trying to make my ...
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### Type K thermocouple durability in semimolten plastic

I want to measure the temperature of a semi-molten piece of plastic, but for my final application I don't want to have to touch the thermocouple. This means it will more than likely end up in the hot ...
1k views

### Where is the cold junction on the commercial thermocouples?

According to all textbooks and articles, a thermocouple must have a cold junction somewhere on the middle of it. But none of the commercial products have a middle point or a marked spot for ...
97 views

### Convert body heat to light [closed]

What thermoelectric device would I use to power one white LED generated by the body heat of one square centimeter skin on a hand. That is, I wish to power one white LED from the heat generated by one ...
305 views

### Can electronic components work without power?

Can electronic components work without power,with the help of temperature? according to my knowledge,I don't think so,until heat will generate some energy and that will drive component. I have to make ...
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So I am struggling with a problem, i am sure someone would have faced. I have a RAMPS shield with a arduino Mega working as the brain of my printer Temperature readings from the heater thermocouple ...
3k views

### Can I use a BC547 NPN transistor as a thermometer?

In the article Electronic Thermometers for Brewers Ken Schwartz talks about how to use a 2N4401 to create a diode thermometer: I attempted a similar setup with a BC547 transistor ( BC547 Transistor ...
4k views

### Pt100 wires to make Wheatstone Bridge

I'm currently trying to build a circuit on a breadboard that, through a temperature sensor, gives off a voltage which I need to amplify. I'm using a Pt100 sensor with 3 wires (red, blue and yellow) ...
1k views

### Replacing the thermocouple for a multimeter?

I bought a no-name but decent multimeter, and it came with a thermocouple. Let's say I broke it in some way. Can I just replace it with any other thermocouple, or is each thermocouple calibrated for ...
221 views

### What is this kind of temperature sensor called (Analogue Devices TMP36)?

I am reading about this stuff, and I have found clear definitions of thermocouples and thermistors online, eg on Wikipedia. But then I also found something different, e.g. what they at AdaFruit just ...
815 views

### What is this component in series with my water heater's thermocouple?

The other day we had our water heater go out and the issue was diagnosed to a faulty thermocouple. When the repair man removed the faulty thermocouple he noticed the following disk-like component in ...
399 views

### Type-K Thermocouple interface problems

I'm trying to interface to a type-K thermocouple with an ATXMEGA128A4U and have been experiencing some difficulty and I'm hoping someone can confirm the process I am using. Details.. 1. TC is ...
290 views

### Fast-stabilising skin temperature sensor

We're currently trying to build a portable temperature sensor for the purposes of estimating human core temperature. This is a bit of an engineering problem (more to do with choice of materials than ...
2k views

### Thermocouple reading different from Commercial Datalogger when using Arduino

A K-type thermocouple is connected to a thermocouple breakout board that outputs 1.2V to 8.8V that covers the entire -260C - 1380 °C of K-type thermocouple. This output is than divided by ...
88 views

### Thermoelectric couple heating on both sides [duplicate]

In college my physics professor showed us a thermoelectric couple powering a fan. He also explained how if you apply a current it cools one side and heats the other side. I have been working on a ...
503 views

### Thermocouple amplifier - single-ended vs differential?

When connecting a thermocouple to an amplifier, what are the advantages of the differential versus the single-ended configuration?
3k views

### Grounded thermocouple vs “grounded” thermocouple

I'm having problems with documentation and what appears to be conflicting use of the word grounded. The way I understand it, a thermocouple can be [grounded, ungrounded, or unsheathed] (http://www....
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### Thermocouple on a grounded stainless steel box

My present project is a ~6kW switching converter in a sealed stainless steel box. The box is grounded well. When I put a thermocouple on the surface of the box, the reading is noisy. Even if I put ...
3k views

### Measure 0-10V using Arduino

A thermocouple amplifier outputs a voltage range of 1.2V to 8.8V for the temperature range -260C till 1380C when using a K-type ...
362 views

### Amplifying signal from the copper wires of two type T thermocouples

My apologies if this is too localized, but I am really in a bind. I am attempting to amplify the voltage difference (so to be read on an arduino) between two thermocouple's copper wires, as pictured ...
427 views

### Salvage data from a reverse connected thermocouple?

My SAE Baja team had a competition this past weekend, and we were using some thermocouples in order to get some temperature data on the drivetrain and engine. They were hooked up right before the ...
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### Time Proportional control

I am developing application for Time Proportional Control of thermostat. I know that the output for heater is proportional to an error. For example, if SetPoint is 20 and proportional band is 2, in ...
980 views

### PCB mount thermocouple socket

I am designing a product that uses a thermocouple to monitor temperature. I am trying to decide what is the best way for users to attach the thermocouple to the PCB. I have found the connectors that ...
364 views

### Operating limit of K-type thermocouple probes

I was looking to purchase a K-type thermocouple and noticed something peculiar. Wikipedia says it can withstand temperatures up to +1350 °C, but Amazon sells some K-type thermocouples that only go up ...
783 views

### How to power an LED with a thermocouple

I'm looking for a device that can convert mV to the minimum required to power an LED. I'm thinking of having a thermocouple or thermopile that will be heated by a constant flame. I've talked with ...