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Questions tagged [thermocouple]

A thermocouple, is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. The voltage across a thermocouple is governed by the Seebeck effect. Thermocouples are widely used as temperature sensors.

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Can I Wire a Thermocouple Like a PT100 Sensor

I have an IoT multi-channel controller which can accept PT100 sensors (2-wire or 3-wire). I don't have any PT100 sensors, however I do have K-type thermocouple wire. Is there any way to wire in the ...
Kendric Rendle-Short's user avatar
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MAX6675 SPI communication with PIC microcontroller

I'm using a PIC16F1832X to communicate with a MAX6675 thermocouple-to-digital converter. As I read the values of the temperature and the SSPBUF register, they are way too high; SSPBUF is 223. I assume ...
wqeeekendwrrar's user avatar
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How do people ground cable shield on thermocouple cable?

I am building an electronic controller that measures the temperature on a metal chamber. Type K thermocouple sensors are placed on the metal chamber, and type k thermocouple extension cable connects ...
Open_Hamster3337's user avatar
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Thermocouple vs NTC

I want to test the accuracy of the NTC soldered in a current sensing board with a shunt resistor. For that, I attached a thermocouple type K to the junction of the shunt using epoxy and applied a ...
404's user avatar
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Cold junction temperature measurement in Multichannel Thermocuple

In a multi-channel thermocuple signal conditioner (for example, 5 channels on a single PCB), should I add 5 separate junction temperature measurements to the thermocuple input of each channel to ...
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What is the purpose of the op-amps connected back to back in a thermocouple signal conditioner?

I am trying to design a thermocouple signal conditioner. I came across this structure on the Analog Devices LTC2057 typical application page. Why was such a connection made instead of using a single ...
Electronx's user avatar
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Amplifying op-amp thermocouple circuit

I am trying to simulate a thermocouple amplifying circuit for a project, and for some reason, my output keeps producing a square wave, rather than a sinusoidal wave. I found this diagram online on a ...
Kevin Martinez's user avatar
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Testing thermocouple functionality

I am currently working on diagnosing the functionality of a thermocouple from a vintage gas stove, whose safety valve does not stay open with the pilot light heating the hot end of the thermocouple. ...
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T12 soldering station problem

I am trying to make a “cheap” t12 based soldering station. However there is a problem. Since T12 tips have the thermocouple and the heating coil in series, you have to turn the driving MOSFET off, ...
De PuP's user avatar
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Turning power on to relays interferes with thermocouple reader

I have 6 3V reed relays SIL03-1A72-71D that connect to a raspberry pi pico directly via gpio pins 11, 12, 13, 14, 15, 18, and 19 on a custom pcb. The connections to the relays are: 1 is connected to ...
notanickel's user avatar
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two thermocouples not reading the same room temperature as a thermometer

(probably operator error/ignorance...) Trying to read room temperature to verify accuracy of the meter readout w/ K type thermocouple - I have four devices: Tektronix DMM916 multimeter w/ K type ...
tomRmalcolm's user avatar
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How can I connect a 3 wire RTD to a 2 wire system

I received a thermocouple replacement part from a machinery company. It has 3 wires (white, black, green/yellow), but the thermocouple it is replacing only has 2 wires (white, red). Can I use the ...
Maxthecat's user avatar
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Setting the parameters of PID for 10 °C set point

I have a PID controller (REX C100), connected to a TEC1-12706 (Thermal Electric Cooling) and a thermocouple K-type. I want to set 10 °C on my PID. The problem is that the actual temperature in PID is ...
Hamed's user avatar
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Best method to sense low temperatures while using low current

I need to measure temperatures of -80C, and the circuit needs to be battery-powered. So I thought an RTD probe with the MAX31865 RTD-to-Digital Converter would work well. I am using an nRF52840 for a ...
MattG's user avatar
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Output voltage thermocouple amplifier decrease when temperature increase

To detect surface temperature of heating foil, I decided to use thermocouple of type K. To amplify the small signal I choose the thermocouple amplifier with cold junction compensation integrated, ...
stefyanna's user avatar
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Temperature sensor on a long wire (100ft) [closed]

I'd like to monitor the temperature of a variety of locations around my house but I don't want to rely on wireless technology. Are there temperature sensors that can be connected over long distances (...
Ben Vitale's user avatar
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Knowing the transfer function of a system and the output, how can I get the input?

I have a system composed by k-thermocouple + metal handpiece, the thermocouple is drowned into the handpiece. If I manage to estimate a transfer function of the system so-made, for example trough ...
jaster's user avatar
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2 votes
2 answers
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I need to make a makeshift thermocouple given limited resources in the third world

I'm living in a part of the world where scrap electronics are hard to come by. Recycling these are big money in the impoverished SEA region I'm living in. I have a Fluke 289 with a type K thermocouple ...
Aaron Butkovich's user avatar
1 vote
1 answer
575 views

How to correctly ground/isolate a grounded enclosure type thermocouple?

My K-type thermocouple (grounded enclosure type) connected to MAX31855 adapter connected to Arduino Mega gives me faults every few readings. It's really, really bad. I've tried swapping thermocouples, ...
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Should op amp reference terminal be connected to ground?

I would like to amplify the voltage from my thermocouple and had a couple of INA122s on hand. This is from the datasheet. Should pin 5 be connected to GND? (pin 4)
couldabin's user avatar
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How do I make sense of the solution to this circuit analysis problem?

I am studying MIT's 6.01 on OCW and have been struggling with a sample final exam problem that involves circuit analysis with op amps. I'm hoping to get some guidance on how to approach the problem or ...
Coder1913's user avatar
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Can I solder this cartridge heater to this thermocouple?

I'm trying to make a vaporizer pipe as a hobby project. The idea is that when you inhale from it, air passes by a cartridge heater and then goes through some "herbs". A thermocouple is used ...
Paul's user avatar
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How to power a peltier element with something portable?

Actually the question is bigger. I will start from the beginning. I want to make a surface, which I can carry in a bag with me, and when I turn it on I want a given part of the surface to become very ...
Angel Miladinov's user avatar
7 votes
3 answers
719 views

Can an op-amp reduce its own gain after a failure?

I have a pellet stove that after few minutes from startup turns off. I discovered that the cause is the smoke temperature that is too low (~ 30 °C, read on the remote) even when it's burning. Of ...
Mark's user avatar
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359 views

MCP9601 constantly indicating open thermocouple

While trying to get temperature values from my thermocouple amplifier, I am able to read the cold junction temperature, yet the hot junction temperature isn't even measured by the converter. Reading ...
drydre's user avatar
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Please fix my broken understanding of this simple thermocouple circuit

Here's my qualm: As per the diagram, I can't understand how the trim probe (resistor) affects the meter reading for this thermocouple circuit. If I understand the diagram correctly, everything is ...
Bumblingidiot's user avatar
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2 answers
217 views

Thermocouple measurement on PCB trace

Good day I have not used thermocouple before. I only know the basic principle. From what I understand, the voltage produced is due to the dissimilar metals with their joined ends being applied with ...
user139731's user avatar
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Thermocouple parallel reading

I need to read 5 thermocouple sensors from a plastic injection machine. I want to use a MAX6675 because it has a cold junction compensation feature. I can achieve parallel readings with 2°C offset in ...
ugur.s's user avatar
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Thermocouple readings affected by PE

I designed a controller for an electric pizza oven. The PCB has an MP-LDE03-20B0 power supply module on it. Everything works great except for measuring the temperature in the oven. I use thermocouples ...
Marek's user avatar
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TECs: parallel or series? [closed]

My project is regarding the cooling effect of TECs. I am from a mechanical background. My question is: what happens when TECs are connected in series or in parallel? If one configuration is better ...
Arun Bhaskar Karanayil Anil's user avatar
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1 answer
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IR and thermocouple measurement difference on large and high emissive objects

First of all, the question is similar to this one. I am working on a high-power, high-density power supply where the size and heat dissipation are quite limited. In the final product, the PCB will be ...
Rohat Kılıç's user avatar
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1 answer
801 views

K-type thermocouple alumel/chromel soldering

I am using a K-type thermocouple for my project. I want to to use a connector which has alumel and chromel pins, but there is a problem there. Is it possible to solder alumel/chromel pins to a PCB?
jacks's user avatar
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Sampling bottleneck due to sensor conversion time? MAX6675/MAX31855

The datasheets for the MAX6675 and MAX31855 say that their "temperature conversion times" are 220 ms and 100 ms respectively. I am using an arduino to get the data from a K-type ...
Atharva's user avatar
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1 answer
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AD620 input voltage range identification

I wish to buy this AD620 amplifier module for amplifying my strain gauge voltage. I also wish to use it with my thermocouple. Basically, I want to accurately read DC voltage values from around 0.1 mV ...
Atharva's user avatar
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How can I read a thermocouple situation with an ESP32

The thermocouple has two pins (a ground, a 0 to -0.0004 when activate the bobbin to run the gas.) I want know how can I detect whether the gas is open or not without adding a sensor to the system. ...
ahmad reza safari's user avatar
1 vote
1 answer
388 views

Picking TVS and ferrite beads for MCP9600 thermocouple converter

I'm about to use the MCP9600 thermocouple voltage to I2C converter for the first time. Because I need my output to be as precise as possible, I decided to apply the recommended circuit shown in figure ...
drydre's user avatar
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2 answers
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Thermocouple short-circuit detection

I'm trying to figure out how to detect a shorted K-type thermocouple (between the wires, not a wire to GND or Vcc.) I would define a short as thermocouple resistance < 0.1 ohm as opposed to 1 ohm ...
Hyp's user avatar
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Why is RTD immune to electro-magnetic fields? [closed]

Thermocouples may have added voltage & induction heating induced in a magnetic field, throwing off the measurements. A Resistance Temperature Detector (RTD) is said to be a good alternative. Why ...
FlakR's user avatar
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Attach thermocouple to a PFC inductor

The inductor I am talking about is simply a toroid. I am attaching a thermocouple junction to this component with help from thermal paste and aluminum tape. Anything I should be careful about in this ...
FlakR's user avatar
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-1 votes
2 answers
968 views

Can a K-type thermocouple measure both air and surface temperatures? [closed]

I want to use a K-type thermocouple to measure exhaust gas temperature and surrounding structure temperatures for my micro turbo jet engine. I read in the comments of How to use MAX6675 thermocouple k ...
Atharva's user avatar
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5 votes
2 answers
492 views

Thermocouple circuit not outputting expected values

My application requires 11 thermocouples to be sampled and logged. Below is the circuit diagram, containing a differential and common mode filter, non-inverting amplifier (gain 111) and a second order ...
AngusE's user avatar
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4 votes
2 answers
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Can I make a homemade Peltier module with constantan wire?

I'm trying to make my own Peltier module. I ordered constantan wire, which I used as N-type semiconductor and iron wire as P-type. I made this and powered it with 3V, but without response. What am I ...
PO12's user avatar
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1 vote
1 answer
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Thermocouple actuated switch

So first of all, I'm a mechanical engineer and a terrible electrical engineer. I'm trying to build a failsafe for a heating element. This heater has an integrated k-type thermocouple and is limited to ...
Wouter's user avatar
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1 vote
2 answers
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Will reversing the polarity of a K thermocouple damage it?

I have a K thermocouple connected to a MAX31855KASA+T IC supplied by 3.3V. I mistakenly reversed the polarity and was taking reading from it for about 1hr. I am noticing the instrument is now ...
Feynman137's user avatar
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3 votes
2 answers
226 views

Can a thermocouple be encased in a custom stainless steel tube?

I would like to read the temperature of oil in a metallic vessel. However I'd like to route the thermocouple so it stays out of the way. Is it OK to just insert the "naked" thermocouple &...
Alessio Sangalli's user avatar
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1 answer
123 views

Temperature circuit not functioning

I am attempting to help mentor some high school kids on circuits and obviously not doing a very good job. We are trying to get a prototype PCB working that uses a max31856mud datasheet and k ...
Feynman137's user avatar
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Landing a Thermocouple on a surface with voltage present

I am connecting multiple K-type TCs (thermocouples) to an electric engine prototype. I have had a problem with the TCs having up to 150 volts on them when the engine is running. I don't know the ...
Greenhorn's user avatar
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580 views

Thermocouple IC MAX31856 circuit what is DRDY

I have a prototype board that seems to only output non-sensible values for K thermocouple readings, with no response to actual temperature changes. Prior to this a breakout board with this exact IC ...
Feynman137's user avatar
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2 answers
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Furnace circuit ideas: constant temperature with thermocouple & heating element

I am wanting to make what we will just call a furnace that will always operate near 1800°F. I'm looking for circuit ideas or a direction in order to maintain the temperature of the furnace. The ...
4DF's user avatar
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Thermocouple bias with LTC2053

This LTC2053 application note shows a thermocouple bias using two 10 MΩ and two 1 MΩ resistors. I understand the idea that the power supply is divided by two 10 MΩ resistors for good common mode ...
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