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Electrical Engineering Rules of Thumb
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Terms in this set (22)
Electricity is fundamentally
charges, both positive and negative
Energy is
work
The are just as many ____ in both a conductor and insulator
positive and negative charges
In a good conductor, the electrons
move easily, like liquid water (electron sea)
In a good insulator, the electrons
are stuck in place, like frozen water
Like charges ___ and opposite charges ___
repel, attract
Electrostatic fields create
static cling, lightning bolts, etc
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
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.
...
Power =
Voltage x Current
The function of a resistor in an electrical circuit is equal to
friction. The resistor resists the ﬂow of electricity just like friction resists the speed of the box. And, guess what? It heats up as it does so. An equation called
Ohm's Law describes this relationship:
resistance = voltage / current
Ohm's Law
resistance = voltage / current
law of inertia
You notice that it takes some work to get the box going, but once it's moving, it coasts along nicely. In fact, it takes work to get it to stop again. How much work, depends on how heavy the box is.
Mass resists a change in speed. Correspondingly, inductance resists a change in
current.
mass = (force * time) / speed
inductance = (voltage * time) / current
Capacitor
has the capacity to store energy. (similar to a spring)
capacitance = (current * time) / force
The inductor is the inverse of
the capacitor
6 Basic Formulas
■ Ohm's Law
■ Voltage divider rule
■ Capacitors impede changes in voltage
■ Inductors impede changes in current
■ Series and parallel resistors
■ Thevenin's theorem
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