电气工程及其自动化专业英语

向青

目录

  • 1 Basic Concepts of Electric Circuits
    • 1.1 Introduction
    • 1.2 Voltage and Current
    • 1.3 Power and Energy
  • 2 Basic Laws of Electric Circuit
    • 2.1 Ohm's Law
    • 2.2 Kirchhoff's Laws
    • 2.3 Series Resistors and Voltage Division
    • 2.4 Parallel Resistors and Current Division
    • 2.5 Summary
  • 3 Capacitors and Inductors
    • 3.1 Capacitors
    • 3.2 Inductors
    • 3.3 Summary
  • 4 Electronic System
    • 4.1 Introduction
    • 4.2 Electronic System Block Diagrams
    • 4.3 Information Processing Versus Power Electronics
    • 4.4 Analog Versus Digital Systems
    • 4.5 Conversion of Signals from Analog to Digital Form
    • 4.6 Relative Advantages of Analog and Digital Systems
  • 5 Operational Amplifiers
    • 5.1 Introduction
    • 5.2 Operational Amplifiers
    • 5.3 Ideal op-amp
    • 5.4 Inverting Amplifier
    • 5.5 Noninverting Amplifier
  • 6 Digital Logic Circuits
    • 6.1 Basic Concepts and Introduction
    • 6.2 Electrical Specifications for Logic Gates
  • 7 Transformer
    • 7.1 Introduction
    • 7.2 Construction of Transformer
    • 7.3 The Ideal Transformer
  • 8 Electrical Machines
    • 8.1 A Brief Overview
    • 8.2 Induction Machines
    • 8.3 Synchronous Machines
    • 8.4 Direct-Current Machines
  • 9 Automatic Control Systems
    • 9.1 Introduction
    • 9.2 Block Diagrams and Transfer Functions
    • 9.3 Open-Loop Control
    • 9.4 Closed-Loop Control: Feedback
    • 9.5 Objectives of a Control System
    • 9.6 Assignment
  • 10 Measurement
    • 10.1 Introduction
    • 10.2 Statistics
    • 10.3 Operating Characteristics
    • 10.4 Measurement Instruments
    • 10.5 Velocity Measurement
  • 11 Power Semiconductor Switches
    • 11.1 Introduction
    • 11.2 Thyristors
    • 11.3 Metal-Oxide-Semiconductor Field Effect Transistors
    • 11.4 Gate Turn-Off Thyristors
    • 11.5 Insulated Gate Bipolar Transistors
    • 11.6 Desired Characteristics in Controllable Switches
  • 12 Rectifiers and Inverters
    • 12.1 Introduction
    • 12.2 Basic Rectifier Concepts
    • 12.3 Practical Thyristor Converters
  • 13 Academic English
    • 13.1 Vocabulary
    • 13.2 Structure
    • 13.3 Common errors
Power and Energy

Measuring Energy vs. Power

Although it is not possible to directly measure energy, the work done can be defined and measured. The methods involves using a calorimeter, which measures the heat absorbed or released in chemical reactions or physical changes, thermometer, which measures temperature or bolometer that is employed to measure the intensity of radiation. Energy generated can be stored whereas power cannot.

Since power is energy per unit of time, in theory it can be calculated after measuring the energy used per second. When calculating the real power consumption of an electrical device, it is essential to measure the voltage applied and the current consumed, taking into account the power that is dissipated in the circuit.

Difference in Units

Energy is usually measured in Joules, the other units include ergs and calories. Power is measured in Watts, which is Joules per second, or ergs per second. Machine are usually described by its power rating, the higher the number the more powerful the machine.