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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137 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
52 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
46 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
156 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
54 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
44 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
146 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
48 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
78 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
97 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
116 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
178 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
97 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
98 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
250 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
137 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
119 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 ...
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3answers
323 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
1k 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 ...
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1answer
114 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 ...
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3answers
136 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
305 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
160 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 ...
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1answer
241 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
263 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
299 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
184 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
244 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
163 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.
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2answers
187 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
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4answers
229 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
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1answer
137 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 ...
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2answers
483 views

Wheatstone bridge calculation

R4 is thermistor with R25 value of 5 Ohm, Beta is 3150. ...
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1answer
176 views

Can I change the input voltage for this temperature-controlled fan circuit:? [duplicate]

Possible Duplicate: Can this temperature-controlled fan circuit be modified for different input voltage? For the above temperature-controlled fan control circuit which is originally ...
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4answers
1k views

How to get A, B and C values for this thermistor?

I wonder if it's possible to extract A, B and C values for TTF-103 thermistor from datasheet. Those values needed to calculate resistance using Steinhart–Hart ...
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3answers
621 views

How to change an LED with a thermistor

I was thinking about buying a thermistor and a RGB LED and thereby be able to change the light of the LED, but I'm confused by the resistances I see on eBay. I see some of 100 ohm, 10k ohm and 100k ...
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2answers
255 views

Thermistor measuring

I need to acquire the temperature of a box thanks to a thermistor. I am wondering how to do that with a really high precision. Here are the caracteristics of the thermistor: T° ...
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2answers
208 views

Is there a way to wire a digital display into a thermistor input to read the value of that thermistor?

I have a solar thermal system on my house and that system is run by a differential temperature controller having two thermistors. The controller does not have any kind of readout on it, thus I have no ...
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5answers
787 views

Is this an RC filter?

I'm trying to understand this temperature sensor circuit I came across on a room Air-Conditioner controller (Want to build one myself). The sensor is an NTC type thermistor (15k at 25 deg C). What ...
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1answer
128 views

Determining values of thermistors

I was wondering if anyone could help me identify these thermistors. They were included in a grab bag I recently purchased and I haven't been able to find any information about them. The numbers on ...
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5answers
4k views

Temperature sensors for an Arduino sous-vide project

I'm creating a PID controller for sous-vide, like this one, and am trying to decide which temperature sensor to get. Priorities: Cost: < £25 delivered in the UK Accuracy: +/- 0.5C Range: 0 - ...
5
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1answer
780 views

Drift and “flipping” in Instrumentation Amplifier reading thermistor

Disclaimer: I only have about 2-3 months of semi-intensive electronics experience. Note that the chip (to the left of the Arduino, is Analog Digital's AD623 Instrumentation Amplifier) Datasheet ...
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0answers
603 views

Voltage Fluctuations in Arduino-opamp-thermistor circuit [closed]

I'm working on a board that takes measurements of voltage off a thermistor through an Arduino and amplified by an opamp (really an instrumentation amp AD623), also there are two potentiometers. See ...
3
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3answers
1k views

Compare resistance to a setpoint and trigger a relay

I want to compare a PTC thermistor to a set point, and trigger a relay if the temperature goes below a set temperature. In particular, my temperature to turn on the relay should be 33 degrees F (845 ...
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1answer
564 views

ROV (underwater) temperature sensor design considerations

I'm the 'technician' for a SeaPerch ROV team (since I know the most about electronics) and I need an underwater temperature sensor able to mount on a ROV. Since I don't have much experience with ...
5
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1answer
844 views

Operating Temperature Range question for Inrush Current Limiting Thermistors

I have a friend who has brought me a circuit board from her flat screen TV. She assumed it was bad because the TV no longer turns on and there was off-white stuff leaking out of some of the ...
9
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3answers
2k views

Op Amp circuit not behaving as desired

Found a circuit on the net that should do exactily what I want (control a cooling fan) but it is 'on' all the time. Not sure if there is an error with the schematic or if there is something else I've ...
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4answers
4k views

Differences between thermistors and thermocouples

As I understand it, both thermistors and thermocouples are temperature sensors. So what are the advantages/disadvantages of using one over the other to measure the temperature? What are the specific ...
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859 views

NTC temperature help

I just started writing a program that represents the temperature of an NTC TT102 thermistor. First I tried the famous voltage divider, but I soon found that it is not good. So I decided to uses the ...
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4answers
427 views

Alternative to NTC Thermistor

I am designing a system which turns on at 45 degC. I want to place a device in series with my circuit that ideally has infinite resistance below 45 degC and then 0 resistance above 45 degC. I guess ...