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Questions tagged [thermistor]

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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42 views

Where better to pull the NTC thermistor? To earth or VCC?

I have a NTC thermistor, resistance 10k. In various examples, thermistors pull either to the ground or to the VCC. The question is, is there a difference and what is safer?
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Bluetooth board with NTC thermistor connector

I have a Bluetooth amplifier board that requires an NTC thermistor connection in order to work from a 7.4 V battery pack. I have trouble finding a protection board for a 18650 pack with the NTC ...
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55 views

Is there a difference between a tempco resistor and a thermistor?

That is, other than just the nomenclature.
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NTC Project (Wheatstone Bridge + Instrumentation Amplifier) - Stuck!

I've been lurking through these forums for years but just now had the urge to ask for help. I'm creating a thermometer (using an NTC thermistor) for my college project. I began to analyze my sensor ...
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37 views

Can a Current Limiter Power Thermistor be used in line to reduce the brightness of a 120v incandescent bulb?

I have an application were I do not have the room for a dimmer switch but need to reduce the lumens of a 120v 25w incandescent bulb just a bit. There used to be a product called the Bulb Saver Button ...
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67 views

How to calculate resistance to use along with NTC 103 thermistor to measure temperatures between 0-100 degrees celcius

I am a complete noob to temperature measurement. I initially tried to measure temperature using LM35 but i got negative values at room temperature and the values were fluctuating a lot. I want to try ...
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60 views

Motor/MOSFET Does NOT React To Input On Breadboard

So I have tried so many different variations on breadboard of this circuit but the motor seems to just be powered by the power rail on breadboard. It does not react to any change in the input and ...
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69 views

How do I identify and work with this thermistor

I've got a PTC thermistor, as pictured. It's being used to detect the output temperature in an in room eletrothermal storage (ETS) unit from Steffes. One of them fell out. It's like some kind of ...
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152 views

Power Supply Design Help- failure at higher currents

I am trying to design a 60V 6A supply to power a power amplifier. Here is the circuit I have so far. Feel free to open it in Circuit Lab and play around: simulate this circuit – Schematic ...
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1answer
103 views

Strange NTC behaviour: it goes open circuit when cooling down

My partner has a heater for heating wax that is used for waxing legs and other body parts. She told me it stopped working; it does not heat up anymore. When I opened the device and looked at it I ...
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54 views

How do I determine whether a sensor is a thermocouple or a thermistor?

Is there any nondestructive way to determine wether a soldering iron uses a thermocouple or a thermistor? The documentation on the iron claims it is a PTC ceramic heater. Some manufacturers mention ...
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100 views

Can you explain the 3 terminals that PTC thermistors have

Okay, so I found from Amazon a cheap PTC thermistor with a fan, just search "Zerodis PTC" and you find it from there. I see it has 3 terminals, also other PTC elements do. Since it's a semiconductor ...
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53 views

How to reduce inrush current for DC Motor in boom barrier gate application?

I'm using 24V 25W 100RPM DC geared motor for boom barrier gate application.So I added an overload protection for that circuit but whenever the motor starts the inrush current is produced and it ...
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62 views

Can resistors be used to bring a heating element within range?

I have a replacement 24V/60W desoldering gun I would like to modify for use on my Aoyue Int958A+ soldering station. My 968A+ has a smoke absorber which has enough suction to double as a solder vacuum. ...
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50 views

Which temperature transducer has these characteristics?

The resistance temperature characteristics of a temperature transducer is show in the figure below, The transducer in question is which of the following? A) Nickel RTD B) NTC thermistor C) Platinum ...
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132 views

ptc thermistor simulation in proteus

I want to simulate ptc thermistor in proteus.But I need this informations. 1) Thermal Contact Res. (°C/W) 2)Thermal Res. to Ambient (°C/W) 3)Time constant (s) datasheet information of ptc ...
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81 views

1M Ohm Thermistor Circuit voltage drops not adding up

The circuit is wired as follows ...
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533 views

How can I simulate an NTC on LTspice?

I have a schematic for a temperature controlled device which should operate at a particular temperature. For that I am using an NTC, now I have done the math by hand but it is more efficient and ...
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70 views

Inrush current into capacitor bank

Given I am charging a 50uF film cap bank to 500V. Do I need a current limiting resistor or some sort of current regulator to minimize inrush current when i first turn on the power supply and/or limit ...
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200 views

How to read temperature with STM32F103C8T6? [closed]

How can I read the temperature using an NTC thermistor with an STM32F103C8T6 board??
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36 views

Voltage Matching with Thermistor

I am working on a circuit for a science competition, and one of the tasks is cooling a thing of water to a certain temperature (we are doing about 25C to 18C) and then using that to trigger a circuit. ...
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1answer
231 views

NTC thermistor series/parallel resistor calculation for MCP73833 linear Li-Ion charger

I am using MCP73833 which has the following datasheet https://ww1.microchip.com/downloads/en/DeviceDoc/22005a.pdf Internal diagram as follows: They says that "An internal 50 μA current source ...
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116 views

Multiple Parallel LED Drivers with Single Thermal Derating NTC Thermistor

I am looking at powering Some multi color High power LEDs e.g LED engin LZ4 or LZ7 (probably a string of five) using a tps92691 based Circuit these being high power leds it seems wise to include ...
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102 views

How to condition a NTC of very low resistance?

I want to use a temperature sensor which changes its resistance. For 0 degrees celsius its resistance is 0.5325 ohms and for 40 degrees celsius it is 3.264 ohms. Obviously putting it in series with ...
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172 views

Identify uncommon thermistor

I am trying to repair several reasonably expensive pieces of equipment (ABI Veriti thermocyclers) in our lab which report the same error. They were all bought at the same time and must have a bad ...
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108 views

Calculating resistors to go with a thermistor

This battery regulator chip I'm using has a pin for a 10kΩ NTC thermistor to let it adjust the charge rate in response to the battery's temperature. You're supposed to choose two resistors to set the ...
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281 views

thermistor in HC-SR501 PIR

i know the effects of soldering photo-resistor to HC-SR501 PIR module. It then detects movement in the dark only. But can anyone tell me that what is the effect of adding a thermistor to the same PIR ...
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81 views

How to protect NTC thermistors for embedding in cement?

My kitchen at ground floor already has a floor (with floor heating) but it needs to be lifted by 3-5 mm with a very fine cement, on top of which tiles will be installed. I would like to embed a ...
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164 views

Power Supply Fuses and Varistor

I wish to build a little decent power supply for my IoT devices, would like also to implement more protection from the live 230V AC side and I decided to put a fast blow glass fuse in a nice holder, ...
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80 views

Compact thermostat for VCO temperature stability

So I have a voltage controlled oscillator with an exponential input made using the THAT2181 VCA IC. The schematic is shown below - the THAT2181 IC is used to change the C4 capacitor charging current ...
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50 views

Vishay Thermistor Reading Issues

I am using an NCD relay control with 8 channel ADC. I have thermometer that is reading temp of my room to be 70F but the Thermistor Vishay NTCLE100E3 10k is reading 62.26F. The relay board has a built ...
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521 views

NTC 5d thermistor and how to use it

I bought a random thermistor for a circuit I'm planning to build and it turned out to be a NTC 5D-15. I'm trying to build this test circuit: After doing a bit of research, that thermistor resistor ...
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149 views

Contactor/relay rating for bypass function of soft start circuit

I am designing a soft start circuit for a 70KVA, 70A, 480/230 delta/star transformer, since the fuses kept blowing without. I've been using 3 NTC thermistors rated for 80A in series with the lines ...
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213 views

Using NPN transistor as Thermistor emulator

Premium motherboards (Asus Crosshair Hero VII) have T_in 2pin header for 10k thermistor temperature monitoring. Probing around reveals internal voltage divider with ~12KOhm rTop resistor (as per ...
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386 views

Using 3.3V or 2.5V for ADC and powering Op Amp from 3.3V or 5V

So the idea is that AIN1 accepts a 0-5 V signal which is protected against short circuits to 30 V. I also want to connect a thermistor between GND and AIN1 with no external components (resistor and ...
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127 views

Limiting Inrush on AC/DC converter

I created a simple power supply as shown below that results in an unregulated 50VDC which is what I desire. The transformer is rated for 1000VA. It works ... but only if you're lucky enough to turn it ...
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69 views

How efficient are Thermomelectric generators [closed]

How effective is a thermoelectric generator, as in how much electricity would it provide over a period of time vs other methods of energy? is it useful and practical at all? an idea of how you can ...
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353 views

Sourcing 3-lead 3.7v LiPo batteries

I'm attempting to source replacement batteries for some medical devices (digital goniometer, inclinometer, etc.) The markings are: GMB063048 3.7V 800mAh 2.0WH 2010.12.08 R I've found batteries of ...
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153 views

How to connect 2 thermistors for battery protection?

I'm planning to use BQ24100 for charging Li-ion cells connected in parallel. Unfortunately, the cells have to be separated by few centimeters, so I have to use 2 thermistors. So, how to connect 2 ...
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252 views

Calibrating ADC for calibration-free temperature measurement

I have an application for a 10-year completely sealed battery-powered Bluetooth temperature measurement system providing an accuracy of +/-0.5C over a range of 0C to 50C. The device cannot be ...
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144 views

Constant Power Micro Load

I am trying to make a circuit that slowly discharges a multi cell lithium battery to storage voltage. I already have a comparator circuit that can turn on or off discharging. I want to support 2s to ...
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391 views

How to use LM35's temperature as cold junction for K type thermocouple?

I have been trying to built an thermocouple base temperature monitoring system which can measure negative temperatures (say about -150 C). I previously have used max6675 but later on I found out it ...
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61 views

Can I expect a probe thermometer to still work if I cut it short?

I have a kitchen probe thermometer, a bit like this one It's overly long for my purposes, and takes an annoyingly long time to record a stable value. I assume this is because it takes a while for the ...
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144 views

Inrush current NTC calculation

I have some trouble with choosing an NTC to limit the inrush current, where I want to bypass the NTC with a relay after a certain time. The choosen NTC should be one of these here: https://www.mouser....
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Simplifying many window comparators

I have 8 thermistors and I must make sure that each of them is inside a temperature window. They all have the same window and I don't care which or how many are inside the valid range, I just need to ...
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1answer
332 views

A way to 'digitalize' a wheatstone bridge

I am currently using a Wheatstone bridge to determine the resistance of a NTC thermistor and feed the difference to the setpoint (analog potentiometer) as the error signal to a PID controller, giving ...
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215 views

What to use instead of 1k1 Ohm PTC thermistor?

I've got uni-t ut60a damaged. IC was replaced. Two tracks were repaired. The PTC thermistor of 1k1 Ohm is left. Unfortunately it is not easily available, in fact I couldn't find any of these being ...
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499 views

Can an NTC sensor drift over time?

I was reading stuff on NTC self heating and I was thinking if the thermal runaway is something that could really affect a measurement. So, not an offset, but actually a drift on the resistance. So I ...
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78 views

How to check the NTC power derating

Reading an NTC datasheet I have understood the meaning of the power derating plot, which looks like this: Meaning that below a certain temperature, the resistance is so high that to allow the 100% of ...
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212 views

PTC Thermistor - Schematic Analysis

I am developing a redesign of a current PCB which uses the attached circuit in order to evaluate the temperature using a PTC thermistor (which is R3 in the given image). The circuit is connected to ...