电子电气工程师必知必会

• 温情杀手

  2020-05-21
  Think of the impedance Z as resistance at a given frequency. As we move on to the other basic equations, keep this in mind. Wherever you see resistance in an equation, you can simply replace it with impedance if you consider the frequency of the signal.
• 温情杀手

  2020-05-21
  Thumb Rules■ There are a few rules in any discipline from which you can derive the rest.■ Learn these rules by heart; gain an intuitive understanding of them.■ Most significant discoveries are only a level or two above these basics.
• 温情杀手

  2020-05-21
  ■ Ohm’s Law■ Voltage divider rule■ Capacitors impede changes in voltage■ Inductors impede changes in current■ Series and parallel resistors■ Thevenin’s theorem
• 温情杀手

  2020-05-21
  Thumb Rules■ Drill the basics; know the basic formulas by heart.■ Get a lot of experience with basic circuits; the goal is to intuitively know how a signal will be affected by a component.■ Break the problem down; draw arrows and notes on the schematic that indicate what the signal is doing.■ Determine in which direction the signal is going; is it inversely related or directly related?■ Develop estimation abilities.■ Spend time on the bench with a scope and simple components.
• 温情杀手

  2020-05-21
  1. You must drill the basics.2. You need experience, and lots of it.3. Break the problem down.
• 温情杀手

  2020-05-21
  Thumb Rules■ It takes voltage and current to make power.■ A resistor is like friction: It creates heat from current flow (resisting it), proportional to voltage measured across it.■ An inductor is like a mass.■ A capacitor is like a spring.■ The inductor is the inverse of the capacitor.
• 温情杀手

  2020-05-21
  Mass impedes a change in speed. Correspondingly, inductance impedes a change in current.
• 温情杀手

  2020-05-21
  There are three fundamental components in virtually every circuit, resistor, inductor, and capacitor.
• 温情杀手

  2020-05-21
  Thumb Rules■ Always consider units in your equations; they can help you make sure you are getting the right answer.■ Use units to create the right equation to solve the problem. Do this by making a unit equation and canceling units until you have the result you want.■ Use estimation to determine approximately what the answer should be as you are analyzing and troubleshooting; then compare that to the results to identify mistakes.
• 温情杀手

  2020-05-21
  REMEMBER THISBy letting the units mean something in the problem, the answer you get will actually mean something, too.
• 温情杀手

  2020-05-21
  In fact, you figure out the units you want in your answer and then work the problem backward to figure out what you need to solve it. You do all this before you do anything with the numbers at all.
• 温情杀手

  2020-05-19
  Thumb Rules■ “Can’t” is a sucker too lazy to try.■ Laziness is the mother of invention.
• 温情杀手

  2020-05-19
  Thumb Rules■ An accumulation of charges is what we call voltage.■ Movement of charges is what we call current or amperage.■ Energy is work; in a circuit the electromagnetic effects move energy from one point to another.
• 温情杀手

  2020-05-19
  The charges in the wire are moving much more slowly than one might think. In fact, DC current moves at about 8CM per hour. (In a typical wire that is, the exact speed depends on several factors, but it is much slower than you might think.)
• 温情杀手

  2020-05-19
  Voltage generates an electrostatic field (it is this field repelling or attracting other charges that creates the voltage “pressure” in the conductor). Current or flow or movement of the charges generates a magnetic field around the conductor.
• 温情杀手

  2020-05-19
  Thumb Rules■ Electricity is fundamentally charges, both positive and negative.■ Energy is work.■ There are just as many positive as negative charges in both a conductor and an insulator.■ In a good conductor, the electrons move easily, like liquid water.■ In a good insulator, the electrons are stuck in place, like frozen water (but not exactly; they don’t “melt”).■ Like charges repel and opposite charges attract.
• 有宁

  2018-05-15
  “Lego” Engineering You can always look up the more advanced stuff, but most of the time a solidapplication of the basics will force the problem at hand to submit to your engineeringprowess. These six rules are things that you should memorize, understand,and be able to do approximations of in your head. These are the rulesthat will make the intuition you are developing a powerful tool. They willunleash the simulation capability that you have right in your own brain.If you really take this advice to heart, years down the road when you’ ve beengiven your “ pointy hairs”9 and you have forgotten all the advanced stuff you used to know, you will still be able to solve engineering problems to the amazement ofyour engineers.
• 一个马甲

  2011-02-13
  电阻=电压/电流质量=(力*时间)/速度电感=(电压*时间)/电流
• 一个马甲

  2011-02-13
  电压*电流=功率阻尼系数=阻尼力/速度
• 温情杀手

  2021-04-09
  Cool application note: using two transistors to switch a signal level Vcc PNP switched by NPN.