This course is a combination of College Physics and Sensor.

Basis

Measuring System

Measurement refers to all operations aimed at determining the properties and magnitudes of objects.

Sensor

input: Physical Quantity/Chemical Quantity/Biomass

output: Electrical quantity

Performance and Evaluation

Bias

  • From sensor’s participation in environment.
  • From improper use by the user or design flaws in the measurement system.
  • dynamic derivation

Calibration

标定/校准

How to Select

  • Holistic need principle
  • High-reliability
  • Cost-effective

Electric Sensor

Resistive Sensor

How to measure?

  • U=IRU=IR

  • Electrical bridge

Capacitive Sensing

C=ϵ0ϵAdC=\frac{\epsilon_0\epsilon A}{d}

Common Physical Effects

Elasticity

弹性

Spring: F=kxF=kx

Strain Parameters for Resistance

电阻应变效应

Piezoelectricity

压电效应

Photoelectric Effect

光电效应

E=hν−W0E=h\nu-W_0

Optical Fiber

光纤

Electromagnetism

电磁效应

Faraday’s law of electromagnetic induction

e=−WdΦdte=-W\frac{d\Phi}{dt}

e=WBlvye=WBlv_y

Hall effect

UH=RHIBdU_H=\frac{R_HIB}{d}

Magnetostriction

磁致伸缩效应

Ultrasonic Transducer

超声波传感器