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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2answers
64 views

Temperature measurement into USB [on hold]

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 ...
0
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0answers
20 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 ...
1
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0answers
137 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
53 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 ...
0
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2answers
49 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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2answers
45 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 – ...
3
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3answers
164 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 ...
0
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1answer
83 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
91 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 ...
0
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2answers
64 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 ...
2
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2answers
116 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 ...
0
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1answer
160 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 ...
0
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2answers
88 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 ...
0
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2answers
36 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 = ...
0
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1answer
48 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 ...
0
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2answers
56 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 ...
0
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2answers
727 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?
0
votes
1answer
161 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: ...
4
votes
3answers
2k 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 ...
2
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2answers
107 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 ...
0
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1answer
144 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 ...
1
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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
95 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
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
185 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 ...
1
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1answer
154 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 \$ \$ ...
0
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1answer
183 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
134 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 ...
0
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3answers
224 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 ...
-1
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2answers
275 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 ...
1
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1answer
128 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 ...
0
votes
1answer
178 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
votes
1answer
512 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
votes
3answers
159 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 ...
0
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1answer
180 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
votes
3answers
725 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 ...
2
votes
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
votes
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
votes
3answers
148 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
votes
1answer
462 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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votes
1answer
282 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
votes
1answer
492 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 ...
1
vote
2answers
497 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
438 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 ...
3
votes
1answer
275 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 ...
1
vote
4answers
385 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 ...
1
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2answers
215 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.
1
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2answers
215 views

What kind of Relay Reacts to Ohms?

I need to connect a relay to my old truck to turn on the "soon to add" electric fans. The ECM has an engine coolant temperature sensor that uses the output resistance to determine coolant ...
2
votes
4answers
251 views

analog circuit to convert one resistance to another

I plan to have a thermistor attached to a CPU heatsink control the speed of a computer case fan. For temperatures below 30c (room temp) I want to stop the fan, and for temperatures at or above 60c, I ...
4
votes
1answer
177 views

Selecting an NTC for inrush current limitting

I am building a small triac valve for ON/OFF control of a 300W heater. The current design problem is as follows. When the heater is cold, it's resistance is low(15 Ohm @ 220VAC), and the initial ...