A device that is used to detect temperature - the word is a portmanteau of thermometer and resistor. The detection mechanism is the measurement of resistance which changes predictably with temperature.

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Choosing the correct thermistor

I need help choosing a thermistor. I’m not sure what I need to look for. Let’s say I have this circuit measuring temperature: I have a range of temperatures from 0 to 10 degrees that I need to ...
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83 views

Suppressing contactor coil inrush, is this possible?

http://www.kvc.com.my/EnterpriseChannel/SharedResources/Datasheet/0/?ProductId=1000066755&Filename=SCHNEIDER-LX4-FH024.pdf I am trying to operate a 24VDC coil with an inrush of approximately 30A, ...
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2answers
77 views

High Precision ADC/DAC Circuit Feedback

This is my first proper circuit I've designed and I'm after some advice. I need a 16 bit DAC, output 0-5V and I need to measure the resistance of a thermistor to 0.1mk accuracy. At the moment, I am ...
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1answer
35 views

How to connect Li-ion batteries with thermistor pin in parallel?

I have a Li-ion charger with 3 contacts: (+) (-) and (TH), based on TP4056 chip. I also have several batteries with corresponding contacts, and the charger does a good job charging them. Now I would ...
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72 views

Fire Alarm Circuit using transistor

This circuit is working inversely on PCB as compare to Proteus Software. In software, when the temperature increases the buzzer is on. This is the desired output, but on PCB this circuit is working ...
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82 views

Constant current source to heat thermistor rapidly

My goal is to heat a thermistor as rapidly as possible. The thermistor has a resistance value of 10k Ohms at 25 degrees C, and a negative temperature coefficient. If I apply a constant voltage of ...
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34 views

LTC1923 TEC controller

I'm planning to use the LTC1923 to accurately control the temperature of a TEC. By looking at the LTC1923 datasheet, on page 26 the suggested circuit employs an instrumentation amplifier (LTC2053) ...
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4answers
83 views

How to apply HT gradually in a valve amplifier?

For valve amplifiers, it is said, that applying anode voltage before the valve is heated reduces lifetime and can have other negative effects on circuit lifetime. To avoid this, I want to add a ...
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4answers
87 views

Low side high side NTC measurement

I am using 100k NTC from Murata (SMD, 0603 package) for temperature Measurement. I will drive NTC (MCU_Output) only when i need to measure the temperature. Which of the following options is better? ...
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2answers
109 views

Determining The Parameters Of A Wheatstone Bridge

Good day, I am trying to use a Wheatstone bridge to condition a thermistor. The arrangement i have is shown in below. I need the following specifications. 10V output max from the bridge at ...
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94 views

does changing the cable length of NTC temperature sensor affect accuracy?

I'm using an off-the-shelf STC-1000 temperature controller, popular with homebrewers, that uses an NTC sensor to read temperature and switch on a relay to cool or heat when the sensed temperature ...
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114 views

Pros / Cons of LM35 and Thermistor, what alternatives?

I'm wondering which benefits/downsides I have using following thermometer? Is there something I'm overseeing? For easy temperature measuring, what would be the easiest? My Opinion is LM35, am I right? ...
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106 views

How to control the temperature of heating element

I am developing a heating application where temperature need to be constant. I am planning to set the temperature @ 200 degree C. when my sensor find the temperature exceeding the set temperature how ...
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2answers
99 views

Heating a li-ion battery for use in sub-zero temperatures

I have a design that I'm working on that is to be outdoors year round, with a 1 watt solar panel trickle charging a 6 Ah li-ion battery during the day. I expect there to be about 3 to 4 months of ...
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3answers
91 views

Could I use a surface mount thermistor to measure ambient temperature?

I'm working on a project where a device I'm using has this thermistor, a Murata NCP15WF104F03RC, to measure the temperature of the device itself. This is a surface mount thermistor. The implementation ...
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2answers
80 views

Temperature measurement into USB [closed]

I am trying to get a couple of temperatures into my computer. In my little lab I have about 50 thermistors that look a bit like this NTC-Thermistor. I now would like to get the temperature of all of ...
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32 views

Do DEOS (watchdog type) fluorescent starters harm lamps?

According to Osram Guide to Starters DEOS Starters (e.g. ST 171): In contrast to the starters in Section 4, the DEOS ® starter has an NTC resistor (negative temperature coefficient) and a ...
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540 views

NTC Thermistor Resistance Calculation for circuit using Wheatstone bridge, Op Amp & Arduino

I'm trying to work out the formula for thermistor resistance when using Wheatstone bridge/op amp circuit as opposed to a voltage divider circuit. I know for a voltage divider the \$R_t\$ value is ...
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2answers
125 views

Inrush Current Limiter Failure

I work for a company that builds electric motors, within the last few years they've started building control boards from brush-less dc motors. On the incoming power we have an Inrush Current Limiter ...
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2answers
67 views

What physical properties differentiates the classes of PT100?

I know how the accuracies are defined by the various classifications of PT100, eg Class A, Class B etc. What is it that is physically different between them?
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58 views

Energy Absorption By Series Resistance During Cap Charging

This question formed while trying to size a NTC thermistor to limit the inrush current to a capacitor. Assume the schematic below (with a fixed resistance): simulate this circuit – ...
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3answers
325 views

Re-building a Crock-pot controller - how are the heating elements powered?

After a few good years, my CrockPot gave up. It looks to me that there may be something wrong with electronics, and being and Arduino enthusiast, I thought I could re-build it. The symptoms are that ...
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1answer
275 views

Surge protection for SMPS

Can an NTC (Negative Temperature Coefficient) thermistor be placed before a MOV (Metal Oxide Varistor) for protecting an SMPS from inrush current and voltage spikes? Here is a drawing to clarify my ...
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272 views

Inrush Thermistor Bypassing

Hi I want to bypass an Inrush Limiter Thermistor. It is between the rectifying bridge and the smoothing capacitors, I was considering using a solid state device. After the rectifer current only flows ...
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2answers
102 views

instrumentation of V-divider dual-thermistor circuit

here's the circuit - voltage divider with 2 matched thermistors ("matched" means close enough that the measured temperatures when thermistors are right next to each other comes close enough for my ...
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2answers
144 views

Lots of thermistors but no readout

Back in Sep '12, Olin Lathrop answered a similar question about wiring a digital display to a thermistor, but my situation is slightly different from Jim McDerby's. I too have solar thermal panels ...
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1answer
479 views

How to place thermistor for reading temperature in NiHM single AA cell charger?

I'm laying out a PCB for a NiMH single AA cell charger following the AVR450 Application Note - Battery Charger for SLA, NiCd, NiMH and Li-Ion Batteries but I'm not sure where to place the NTC ...
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135 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 ...
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56 views

School Task with NTC

I need to solve the task shown on the picture. The first part is to calculate the temperature (in °C) from the NTC when Uv = 2V is. This means Iv is infinite. The given Values are: Uq = 12V, R1 = ...
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94 views

What is the “nominal temperature threshold” (NTT) on a thermistor?

I bought a thermistor together with my Arduino, because I thought it would be a good first project. I should have gone a different way, since it is obviously too complex for my level, but well, now I ...
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2answers
78 views

Max temperature of PTC heater, need tip

I have some difficulty reading specifications for PTC heaters, more specifically the ones on here. I understand that a PTC heater does not, inherently, rise above a specific temperature. In the ...
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2answers
2k views

PWM control of Peltier with Arduino+Thermistor [duplicate]

I currently have this setup and would like to add automatic control over the PWM based on a thermistor reading. Any insights?
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198 views

Where can I find a transistor similar to a 2n 3904?

I have what I believe is a 2N 3904 638 transistor. It measures 50MΩ at around 70°F. How can I find a data sheet on this? How would I go about finding a similar / replacement thermistor? PS: ...
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5k views

Thermistor control of peltier voltage with Arduino (for DSLR chill box project)

I am mildly familiar with electronics, mostly from playing around with electronics kits as a kid. That was a long time ago, though, maybe as much as 20 years ago. I am currently working on a cold or ...
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2answers
183 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 ...
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1answer
215 views

Low Curie Point PTC Thermistor

For a self regulating heater powered by a 12 V battery, I'm hoping to find a ~35 C Curie Point thermistor with a low "cold" resistance (for winter time, << 150 ohms). Most of these PTC ...
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1answer
2k views

Peltier heat resistor temperature controller, schematic issue

I've been having a problem with the following schematic: What I need to do: Two temperature controllers in order to create a temperature gradient. The hot side is a a little above room temperature ...
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1answer
134 views

Thermoelectric cooled Avalanche Photodiode sensor PCB

I'm designing a small PCB (max 5x5 cm) to bias and readout from an Avalanche Photodiode. Since the APD response varies greatly with the temperature, I want to use a cheap 12706 TEC together with a ...
2
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1answer
70 views

Table with termistor models with alfa

Hello I'm searching table with thermistors types and alfa (temperature coefficient). I need alfa for this formula : Mt = 1 - alfa/100*(Tmax - 20) I have some old ...
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3answers
197 views

Cost-sensitive way to maintain a 220C temperature

I'm building a device which is designed to be built by people of varying skill and education levels. Part of it needs to climb to and maintain a temperature of 220C, but I don't need very tight ...
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1answer
273 views

Thermistor calculations using B-Parameter equation

I have a USUR1000-104G as seen here. From what I understand by these links here and here and using the b-parameter equation from wikipedia. I have the following values: \$ \beta = 3890 \$ \$ ...
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1answer
270 views

Trying to get readable value with Arduino/Thermistor setup

I'm trying to get a readable value from a thermistor. Right now it's printing 223.25 as my celsius value in my room. I know this is wrong. I'm using the thermistor model which is located HERE. The ...
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2answers
181 views

I'm getting 512 as a reading from a thermistor. Trying to convert this into something readable but having a hard time

I just recently purchased a KY028 Temperature Sensor located HERE. I was having trouble hooking this sensor up so I snipped off the thermistor and shoved it in a breadboard. I know it sounds tacky but ...
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3answers
369 views

How to trigger something once a day [duplicate]

What would be the right thing to use if I want the base of a transistor to be high for 12 hours and low for 12 hours? I ask because I would like to make a circuit that regulates temperature in a ...
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2answers
402 views

Help me understand this 4-wire RTD circuit

This circuit is a kelvin connection of 4-wire RTD. Resistance element is a 4-wire RTD (PT100). Can anyone tell me what can be the values of the resistors in the arms (RH)? And can anyone explain the ...
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1answer
178 views

What is the simplest way to toggle a relay with analog feedback?

I've been playing with electronics for a long time, but am fairly new to digital electronics, including using Fritzing, so apologizes in advance for that. I'm attempting a fairly basic ...
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1answer
233 views

Circuit or component to detect temperature change

I know this is a very simple question but I didn't find the answer. I have very less knowledge in electrical. I want a component or a circuit or whatever, which I can attach to a heating coil so that ...
3
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1answer
822 views

Simplifying opamp+thermistor circuit

I asked this question yesterday, which got answered and would work, but as I already stacked up on (dual) opamps I might as well do better. I've come up with this (probably flawed..) circuit, to ...
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3answers
185 views

Simplest way to measure 98 to 140 Ohm range with an ADC?

I have a thermistor that should vary between 98 and 140 Ohm and am looking for the simplest circuit that will convert this into something meaningful for a 10 bit ADC in the 0-3.3V range. Precision ...
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1answer
233 views

Constant Sum Voltage Divider With Thermistor/Temp Sensor

I need a circuit with a thermistor/temp sensor that will essentially emulate a pot. In other words, I need a voltage divider that varies with the resistance of the thermistor/sensor, but keeps the ...