The class of electric and magnetic sensors and actuators is the broadest by far of all other classes, both in numbers and types and the variety within each type. Perhaps this should come as no surprise since in a majority of cases a sensor exploits the electrical properties of materials and, with few exceptions, the requisite output is electrical. In fact, we could argue that even sensors that were not placed in this category belong here as well. Thermocouples exploit electrical effects in conductors and semiconductors - an electrical phenomenon. Optical sensors are either based on wave propagation, which is an electromagnetic phenomenon, or on quanta, which are measured through electronic interaction with the atomic structure of the sensor. It would take little to argue that this is an electric phenomenon. In terms of actuation, most actuators are either electrical or, more commonly, magnetic. This is particularly true of actuators that need to provide considerable power. However, for the sake of simplicity and to follow the basic idea of limiting the number of principles involved in each class of sensors, we will limit ourselves here to the following types of sensors and actuators.
Chapter Contents:
- 5.1 Introduction
- 5.2 Units
- 5.3 The Electric Field: Capacitive Sensors and Actuators
- 5.3.1 Capacitive Position, Proximity, and Displacement Sensors
- 5.3.2 Capacitive Fluid Level Sensors
- 5.3.3 Capacitive Actuators
- 5.4 Magnetic Fields: Sensors and Actuators
- 5.4.1 Inductive Sensors
- 5.4.1.1 Inductive Proximity Sensors
- 5.4.1.2 Eddy Current Proximity Sensors
- 5.4.1.3 Position and Displacement Sensing: Variable Inductance Sensors
- 5.4.2 Hall Effect Sensors
- 5.5 Magnetohydrodynamic (MHD) Sensors and Actuators
- 5.5.1 MHD Generator or Sensor
- 5.5.2 MHD Pump or Actuator
- 5.6 Magnetoresistance and Magnetoresistive Sensors
- 5.7 Magnetostrictive Sensors and Actuators
- 5.7.1 Magnetostrictive Actuators
- 5.8 Magnetometers
- 5.8.1 Coil Magnetometer
- 5.8.2 The Fluxgate Magnetometer
- 5.8.3 The SQUID
- 5.9 Magnetic Actuators
- 5.9.1 Voice Coil Actuators
- 5.9.2 Motors as Actuators
- 5.9.2.1 Operation Principles
- 5.9.2.2 Brushless, Electronically Commutated DC Motors (BLDC Motors)
- 5.9.2.3 AC Motors
- 5.9.2.4 Stepper Motors
- 5.9.2.5 Linear Motors
- 5.9.3 Magnetic Solenoid Actuators and Magnetic Valves
- 5.10 Voltage and Current Sensors
- 5.10.1 Voltage Sensing
- 5.10.2 Current Sensing
- 5.11 Problems
Inspec keywords:
electric actuators;
thermocouples;
light propagation;
conductors (electric);
electric sensing devices;
semiconductor devices;
magnetic sensors;
electromagnetic actuators;
optical sensors
Other keywords:
atomic structure;
optical sensor;
semiconductor;
wave propagation;
conductor;
thermocouple;
electric sensor;
electromagnetic phenomenon;
magnetic sensor;
actuator
Subjects:
Magnetic variables measurement;
Conductors;
Magnetic material applications and devices;
Light propagation;
Electromagnetic device applications;
Thermal variables measurement;
Sensing devices and transducers;
Semiconductor devices