NTC calibration and multiple temperature sensors - Revision history

Mol: /* Calibrating using known datapoints */

2024-03-28T07:14:06Z

Calibrating using known datapoints

← Older revision		Revision as of 10:14, 28 March 2024
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	=== Calibrating using known datapoints ===		=== Calibrating using known datapoints ===

			[[File:Thermistor calibrate desmos.png\|thumb\|Thermistor calibration using three measused points]]

	Though the NTC sensor is nonlinear, locally it will be linear. Thus by using some known datapoints the temperature can be estimated.		Though the NTC sensor is nonlinear, locally it will be linear. Thus by using some known datapoints the temperature can be estimated.

	Some known datapoints:		Example. Some known datapoints: R2 = 16200
	* boiling water 100 deg		* boiling water 100 deg gives R2 = 16200
	* room temperature		* room temperature 24 deg R2 = 5885
	* freezing point of water		* freezing point of water R2 = 533

	== LM35DZ ==		== LM35DZ ==

2023-09-20T19:31:51Z

References

← Older revision		Revision as of 22:31, 20 September 2023
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	* https://www.tdk-electronics.tdk.com/download/531116/19643b7ea798d7c4670141a88cd993f9/%20pdf-general-technical-information.pdf		* https://www.tdk-electronics.tdk.com/download/531116/19643b7ea798d7c4670141a88cd993f9/%20pdf-general-technical-information.pdf
	* https://courses.cit.cornell.edu/ece533/Lectures/handout1.pdf		* https://courses.cit.cornell.edu/ece533/Lectures/handout1.pdf
			* http://www.engineeringphysics.weebly.com/uploads/8/2/4/3/8243106/unit_iv_semiconductors.pdf

2023-09-20T19:31:32Z

Some Semiconductor Physics

← Older revision		Revision as of 22:31, 20 September 2023
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	</math>		</math>

			This will give

			<math>
			\rho_e = \frac1{B e^{-\beta \Delta E/2}} = Ae^{\beta \Delta E/2}
			</math>

			which gives

			<math>
			\ln \rho_e = \ln (\beta \Delta E/2 ) + \ln A
			</math>

2023-09-20T19:12:53Z

= LM35DZ

2023-09-20T19:11:34Z

Steinhart-Hart Equation

← Older revision		Revision as of 22:11, 20 September 2023
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	\frac1T = \frac1{T_0} + \frac1B \ln(R/R_0) = a_0 + a_1 \ln (R/R_0)		\frac1T = \frac1{T_0} + \frac1B \ln(R/R_0) = a_0 + a_1 \ln (R/R_0)
	</math>		</math>
	and expand it.		and expand it to infinite series, but use only some first terms.

2023-09-20T19:10:19Z

References

← Older revision		Revision as of 22:10, 20 September 2023
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	* https://www.newport.com/medias/sys_master/images/images/h67/hc1/8797049487390/AN04-Thermistor-Calibration-and-Steinhart-Hart.pdf		* https://www.newport.com/medias/sys_master/images/images/h67/hc1/8797049487390/AN04-Thermistor-Calibration-and-Steinhart-Hart.pdf
	* https://www.tdk-electronics.tdk.com/download/531116/19643b7ea798d7c4670141a88cd993f9/%20pdf-general-technical-information.pdf		* https://www.tdk-electronics.tdk.com/download/531116/19643b7ea798d7c4670141a88cd993f9/%20pdf-general-technical-information.pdf
			* https://courses.cit.cornell.edu/ece533/Lectures/handout1.pdf

2023-09-20T19:09:39Z

Steinhart-Hart Equation

← Older revision		Revision as of 22:09, 20 September 2023
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	<math>		<math>
	\rho^{-1} = F(T) e^{- \Delta E/~~2kT~~}		\rho^{-1} = F(T) e^{- \beta \Delta E/2}
	</math>		</math>
	where <math>\Delta E</math> is the energy gap. However, the thermistors does not have sharply defined energy bands, and thus <math>\Delta E</math> is in doubt. Steinhart and Hart simply used empirical curve fitting with following criteria:		where <math>\Delta E</math> is the energy gap. However, the thermistors does not have sharply defined energy bands, and thus <math>\Delta E</math> is in doubt. Steinhart and Hart simply used empirical curve fitting with following criteria:

2023-09-20T19:09:05Z

Some Semiconductor Physics

← Older revision		Revision as of 22:09, 20 September 2023
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	<math>		<math>
			\begin{align}
	N_C e^{\beta(E_f - E_c)} &= N_v e^{\beta(E_v - E_f)}\\		N_C e^{\beta(E_f - E_c)} &= N_v e^{\beta(E_v - E_f)}\\
	E_f &= \frac12 (E_c + E_v) + \frac12 \beta \ln \frac{N_v}{N_c}		E_f &= \frac12 (E_c + E_v) + \frac12 \beta \ln \frac{N_v}{N_c}
			\end{align}
	</math>		</math>

2023-09-20T19:08:31Z

Some Semiconductor Physics

← Older revision		Revision as of 22:08, 20 September 2023
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	Intrinsic conduction (no doped): <math>\ln RT = A + B/T</math>. It was found that <math>B</math> (<math>\beta</math>) is not constant but dependent on temperature.		Intrinsic conduction (no doped): <math>\ln RT = A + B/T</math>. It was found that <math>B</math> (<math>\beta</math>) is not constant but dependent on temperature. For intrinsic <math>n=p</math> giving

			<math>
			N_C e^{\beta(E_f - E_c)} &= N_v e^{\beta(E_v - E_f)}\\
			E_f &= \frac12 (E_c + E_v) + \frac12 \beta \ln \frac{N_v}{N_c}
			</math>

			and if <math>N_v\approx N_c</math>, then <math>E_f</math> is in the middle of the gap giving

			<math>
			n = p = \sqrt{N_c N_v}e^{-\beta \Delta E/2 }
			</math>

2023-09-20T19:04:00Z

Some Semiconductor Physics

← Older revision		Revision as of 22:04, 20 September 2023
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	Intrinsic conduction: <math>\ln RT = A + B/T</math>. It was found that <math>B</math> (<math>\beta</math>) is not constant but dependent on temperature.		Intrinsic conduction (no doped): <math>\ln RT = A + B/T</math>. It was found that <math>B</math> (<math>\beta</math>) is not constant but dependent on temperature.