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.

Filter by
Sorted by
Tagged with
0
votes
0answers
40 views

Question regarding thermistors and ohmic heating

I am unsure why these answers are so. My attempts were black, the correct answers were red. A test is coming up in 10 hrs so any feedback would be nice. For Q9, I thought thermistors were made of semi-...
5
votes
2answers
186 views

Choosing register value for NTC with voltage divider

I need some help to choose resistor for voltage divider circuit to read temperature using NTC Thermistor. I'm planning to use STM32 with his 12bit ADC. The NTC I'm using has the following properties: ...
2
votes
4answers
365 views

How to turn a normally-closed temperature control circuit into a normally-open one?

I've designed a very simple heating circuit that runs a heater until a certain temperature has been reached (as measured by an NTC thermistor) at which point the heater turns off. The circuit diagram ...
2
votes
2answers
144 views

Linearization of thermistor

Thermistors are highly nonlinear devices . This linearization circuit of a NTC produces a linear response (temperature/resistance).But what should be the values of \$R_{s}\$ and \$R_{p}\$? Image from: ...
1
vote
1answer
42 views

NTC thermistor circuit design - obtaining resistance values

I am trying to solve this circuit in order to compare to regular Op Amp thermistor circuits. I'm using R4 as an NTC thermistor that ranges from 25ºC (6.24kOhm) to 40ºC (2.663kOhm), and VCC as 5V and i ...
1
vote
0answers
32 views

Voltage reference to drive multiple thermistors - high precision with op amp to supply current, or just generic voltage ref?

I would like to drive 8 thermistors in parallel. They will be driven from 2.5V in a voltage divider. This will be about 20mA current draw. I will be using a ratiometric measurement where the ADC ...
2
votes
1answer
113 views

Does NTC temperature measurement need calibration?

I'm creating some temperature sensors for home use. To measure outside and rooms' temperatures. Range from -30 °C to +50 °C. Temperature measurement is based on 10k NTCs SDNT2012X103F3950FTF (B=3950K, ...
0
votes
2answers
81 views

Why did the output voltage of this circuit had the same value no matter what the value for the resistor R2 was

So here is the circuit: R2 is a NTC thermistor (its value changes with temperature) and i want vout, the output of this circuit, to be in between 0.05V and 4.95V, where 0.05V should correspond to R2 ...
1
vote
2answers
150 views

Why does a voltage divider linearize the effects of a non-linear thermistor?

I saw a design specification with an NTC thermistor in a voltage-divider configuration. The design method said that we must have $$R_1=\sqrt{R_{NTC\min}R_{NTC\max}}$$ to produce a linear output ...
0
votes
1answer
72 views

Identify temperature sensor in thermostat

I somehow managed to damage the temperature sensor in my thermostat while cleaning corroded battery contacts. Apparently the only fix is "buy a new thermostat", though it is a pity to ...
5
votes
4answers
609 views

Averaging thermistor readings

I have 9 thermistors arranged in a grid, and I want to average the readings from these thermistors without code (that is, average them in a circuit rather than reading all the values into a ...
0
votes
0answers
41 views

NTC for inrush for DC/DC with DC input voltage

I want to limit the current to my DC/DC input. At first, I wanted to use a resistor, however, I also came across an NTC for inrush limiting. So I basically want to change R1 with an NTC. The specs for ...
1
vote
0answers
22 views

Li Ion cell charging and thermistors

I am designing a circuit to charge a small Li Ion flat cell with a capacity of around 300mAh. I want to charge it at around 75mA to 150mA max in the CC part of the cycle. It will always be charged ...
0
votes
1answer
44 views

Temperature sensing with NTC circuit

I am reading through this document by TI on designing a temperature sensing circuit with an NTC thermistor. I'm having some trouble understanding the design steps though. Here are some snippets from ...
1
vote
1answer
34 views

Using two thermistors instead of one on battery protection IC

I'm making a battery protection board for a 3S1P pack. I wanted to include two thermistors in the pack to monitor the cell temperature because of how I want to position the batteries. The batteries ...
0
votes
2answers
91 views

Is it possible to calculate the optimum load resistor value for a thermistor?

In order to calculate the load resistor for a thermistor, we took the thermistor values over temperature (-40 (1kΩ )--> +86C (320kΩ)) and then tried a variety of load resistor values until the ...
0
votes
1answer
78 views

Need help with a replacement thermistor

I recently bought a used IKEA ceiling light however when getting it home noticed that it seems the live wire is connected to a thermistor? which then has another short wire where you connect to mains ...
-1
votes
1answer
67 views

What can I do to see only the logical values in the MOSFET input?

(Animated GIF of the simulation is here) This is a simple circuit that makes the MOSFET turn off, as the temperature of the NTC thermistor rises. As you increase the temperature in the diagram, the ...
-1
votes
2answers
92 views

Curly Symbol in RTD PTC Thermistor

What is the meaning of the "curly" symbol close to the double up arrows (Positive Temperature Coefficient, PTC) thermistor symbol? . (Ref.1, Ref.2)
1
vote
0answers
46 views

Stm32f103 adc stable conversion

I am making a ntc thermometer with stm32f103c8 (by writing over registers without using state library). The code works as it is,I did the adc conversion in 7.5 cycles. I used the calibration register ...
0
votes
1answer
47 views

Calculate NTC Temprature. but witout series resistor

Hello I have NTC Connected on PCB which configure as shown in following schematics. The problem is that I can not apply Steinhart-Hart equation because there is no resistance connected in series to ...
0
votes
3answers
137 views

How to measure the temperature of a surface using an Arduino?

I'd like to measure the surface temperature of of a metal surface, to see how much that metal surface is heating up. I'm trying to recreate The EngineGuard. The EngineGuard uses a 10mm washer, that ...
0
votes
0answers
13 views

Will a 3S-3P NTC-array improve noise or self-heating?

I recently asked a question, "Tradeoffs for NTC Thermistors regarding 10K vs 100K vs 1Meg etc" where the answer was that noise for the 1Meg NTC would be greatest (10 times that of a 100K NTC....
0
votes
1answer
57 views

How to connect a thermistor to a micro-controller?

I was following a datasheet of a micro-controller and I got confused. I have two thermistors (LM 35DZ & TMP36GT9Z.) I would like to connect them to an evaluation board. The picture shows how: How ...
-1
votes
3answers
130 views

What is the difference in power consumption between thermocouple and thermistor?

I am working on a project to transmit sensor data and I chose to go with a temperature sensor to connect to a micro-controller. Since I care a lot about power consumption for my project, I would like ...
1
vote
3answers
199 views

Tradeoffs for NTC Thermistors regarding 10K vs 100K vs 1Meg etc

I would like to make multiple strings of sensor having about 10 thermistors per string, each wired individually, but terminating at different lengths so that they're evenly spaced along each string. ...
0
votes
1answer
58 views

Picking up EMI when measuring NTC near laser causing board reset

I tried searching for this to no avail. I hope I'm not all too wrong asking it here. I have set up my 60W CO2 Laser with a SKR 1.4 Turbo board and connected a 10k NTC thermistor to measure the ...
1
vote
2answers
66 views

Switch on and off a relay based on two different thermistor values

I am planning to add an electric fan to cool down an old car's radiator based on coolant's temperature. I have a temperature sensor of which I know the resistance/temperature profile. Let's say when ...
1
vote
0answers
59 views

Laser printer heater tricking

I use the toner transfer method to create PCBs. By removing the heat fuser from a laser printer and printing on gloss paper gives me wonderful results. The heat fuser and thermistor sensor is still ...
0
votes
0answers
32 views

I have an MZ4 thermistor, I can't find info about the value of capacitance

I have bought a self assembly kit for power source (based on the LM317). The provided small thermistors are tagged as MZ4. I did my research but couldn't find the datasheet. The PCB is showing them to ...
0
votes
1answer
46 views

Inrush Surge Limiter [NTC Thermistor] on Primary or Secondary side of Linear Power Supply

In designing a linear power supply, I understand I need to limit the inrush surge current on cold start, to charge up the large bank of filter capacitors, post-rectifier. However, my original intent ...
0
votes
1answer
101 views

Using a 10K ohm thermistor as a 5K

I have a water cooler that is using a B3950 10K sensor. For energy saving reasons, the microcontroller is limited to 6 degrees celsius (R=24k for the 10k ohm) I can't modify the microcontroller or how ...
1
vote
2answers
157 views

Why is there a resistor in this circuit?

Why there is a 220 ohm resistor in this circuit? Can't we just connect the thermistor directly to the base of transistor?
0
votes
1answer
45 views

can two separate circuits use the one sensor

I want to monitor the temperature of my washing machine. I was going to connect a raspberry pi up to the thermistor at the bottom of the drum. Would this interfere with how the washing machine ...
0
votes
2answers
140 views

Is this the correct way to make a temperature activated fan?

This circuit is being used outside a PC. simulate this circuit – Schematic created using CircuitLab EDIT: @SupaNova The speed will increase with temp and the cutoff temp is 75℉.
0
votes
0answers
34 views

Need to identify faulty thermistor in order to find a like or better replacement

I have an ic with a poorly performing thermistor I'd like to replace with a more accurate, more sensitive component. The first step is finding out what thermistor I likely have or at least who made it....
1
vote
1answer
116 views

Calculating NTC temperature on Controllino Maxi Automation yields incorrect temperature

I'm using the analog input on the Controllino Maxi Automation to determine the temperature of a 10K NTC thermistor. At first we thought it was a self heating issue given that with 24V the current ...
2
votes
1answer
432 views

What does a 'scaling factor' mean for an ADC?

I'm using the analog input on the Controllino Maxi Automation to determine the temperature of a 10K NTC thermistor. I'm having some difficulty understanding how the ADC works. On a regular arduino ...
0
votes
1answer
45 views

Replacing a NTC in Meanwell Power Supply

I have a query regarding replacing a NTC on a Meanwell dual output power supply. I managed to blow a stepper motor driver and the power supply last night (accidentally swapped a plug to a different ...
0
votes
1answer
22 views

Sensor QT0805X-102J

I needed to use a sensor to measure variations in temperature from inspired and expired air. But since i am doing a simulation in TINA-TI i am limited in the sensors I can use. I thought of using this ...
2
votes
1answer
64 views

Respiratory rate monitor

I have this project to build an instrumentation system to measure the respiratory rate. We decided to use a thermistor to measure the variation on the temperature of the air inhaled and exhaled. To ...
4
votes
4answers
344 views

Output from TD100 with instrumentation amplifier not as expected

I've been having trouble with my TD100 circuit for a few days now and I cannot understand why the output isn't as I expect. This is the process: simulate this circuit – Schematic created using ...
0
votes
1answer
50 views

Driving 18 Thermistors in parallel

I am designing a circuit that needs to have 18 thermistors to measure the temperature at various points. The thermistors are 2metres+ away from the ADC Usually when I power a thermistors I use a Vref ...
0
votes
1answer
68 views

Which thermistor or temperature sensors are less power draining?

I am trying to build a low-power system. One of the system parts is a Temperature sensing circuit (0 <T<60 C). Since I am have limited power (~500 uA 3V). I was lost as to which approach is the ...
0
votes
3answers
66 views

How to operate a lower power thermistor power circuit?

I would like to like to create a temperature circuit that connects to a wireless module (e.g. Bluetooth) to transmit the signal. My challenge is that I have a limited power supply (200 mA - 3.5V) to ...
0
votes
2answers
34 views

simplifying RTD (resistance temperature detector) units

using a RTD, the norms give you dissipation constants in ohm per ohm per degree C, I dont understand as this should simplify to simply degrees C? what is the meaning of this unit? Thanks!
0
votes
2answers
100 views

ADC is giving fault codes when I touch thermistor attached to it

I am working on writing a control program for my pellet smoker. I am having an issue with the meat thermometer that came with the smoker. I have a MAXIM 31865 ADC that is connected to a Raspberry Pi. ...
-1
votes
3answers
431 views

Connecting a thermistor to very long cables

I'm working on a design for a multi-sensor temperature alarm for a greenhouse. I plan on using PTC thermistors as the temperature sensors as I have a few 1k PTCs lying around. Can I connect the PTC to ...
0
votes
0answers
33 views

How to modifiy DC2259A evaluation board to access Vref2 on LTC6811-1 IC? For the purpose of powering external thermistors

I am using a DC2259A Evaluation Board, to monitor battery cell voltages and am hoping to drive external thermistor circuits for the purpose of measuring battery cell temperatures from Vref2 on the ...
0
votes
2answers
76 views

Surface mount thermistor practices

I have a 2 layer board that I am mounting directly to an aluminum housing. The circuit contains a temperature regulation circuit to monitor housing temperature by way of an NTC thermistor. As the ...

1
2 3 4 5
7