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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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
67 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
56 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
68 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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22 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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217 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
60 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
55 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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46 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
183 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
100 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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2answers
110 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
68 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
119 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
200 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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2answers
99 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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39 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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1answer
56 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
58 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
917 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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1answer
163 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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3answers
3k 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
110 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
154 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
1k 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
100 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 ...
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1answer
67 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
186 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
170 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
199 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
140 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
240 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
290 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
134 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
189 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
595 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 ...
3
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3answers
164 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
191 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 ...
2
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3answers
777 views

Arduino Rounding question

I have made a simple thermostat for controlling a 12V heater. The temperature range can be from 0 F to around 190 F. For some reason when the displayed temperature on my LCD goes from 99 to 100 ...
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2answers
3k views

NTC Thermistor circuit, ADC conversion, compute temperature

Here's the schematics of my NTC - ADC circuit, ADC 10bits, ADCVCC 2.56V Vin = 5V Someone can explain me how i get RT, the value of resistance of NTC from ADC value? thanks. I'm using the ...
4
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1answer
122 views

Safely detecting presence of 12v applied via exposed terminals for use with microcontroller

I have a board which contains a microcontroller and a 10k NTC thermistor (B57421V2103J62) wired to two external terminals, one of which is common with the board ground plane. The terminals are exposed ...
5
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3answers
150 views

Water detector for heating element?

I want to run a 300W heating element in a water bath, but I'd like to make sure that it isn't turned on by mistake when it's out of water, so I thought of connecting it to a controller and a sensor, ...
4
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1answer
482 views

Thermistor Datasheet Reading

I have the following datasheet for a thermisistor: http://make-documents.s3.amazonaws.com/UGulDNLaIajWgPom.pdf I am trying to use the formula (found here http:// ...
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1answer
293 views

trying to locate a replacement thermistor

I'm trying to replace a thermistor off a LG lcd tv board. It has SCK 154 818D on the old thermistor. I went to shields and they gave me a ceramic capacitor (NTE 90315) and said it would work. I'm ...
3
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1answer
529 views

How could I identify this thermistor

I've been scavenging for components on a deceased gadget and I've found a thermistor I'd like to use in the future. The problem is there's no serial code printed on it. Without knowing the ...
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2answers
549 views

Will the B constant for 10k ohm NTC thermistors be the same from all vendors?

I recently purchased a 10k ohm NTC thermistor from a local electronics store for which I couldn't find a datasheet. By going through the post How to measure temperature using a NTC thermistor I ...
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1answer
448 views

Picking Thermistor for Low Power Push-Pull Output Amplifier

Regarding the following low power push pull transistor "Deacy" amplifier: what type and value of thermistor might be used as depicted in this graphic: to add temperature compensation to this ...
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1answer
296 views

Replicate thermistor behavior for second sensor

I'm working with an R/C electric motor that has a 10K thermistor sensor built into it, which is connected to a speed control that has basic thermal protection. I would like to build a secondary sensor ...
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4answers
404 views

Can I simulate the temperature response of one thermistor by a different thermistor

This sounds like an automotive question, but its really not. I have a engine temperature sensor (presumably a thermistor, as it reduces resistance with increasing temperature). I need to mate this to ...
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2answers
223 views

Is is possible to produce a resistance that represents the average of two thermistors?

For example, if I want to connect 2 thermistors to a thermostat in a circuit and then return the average resistance between the two of them to the thermostat's ADC.