Download Electrical System

Electrical System
An electrical system uses electricity to perform some sort of work. An obvious
element of an electrical system is electricity which can be defined as the flow of
electrons. Electrons flow from the negative terminal to the positive terminal. When
electrons are carefully controlled using various components usually located on a circuit
board this is known as electronics.
Conductor: A conductor is a substance that easily allows electrons to flow through it.
Examples of conductors would be: iron, copper, aluminum, & water. Metals tend to be
good conductors of electricity because they usually have "free electrons" that can move
easily between atoms.
Insulator: An insulator is a type of material which does NOT allow electrons to flow
through it. Examples of good insulators would be: plastic & rubber.
Semiconductor: A semiconductor uses a material such as silicon to control how much
electricity flows through it. A diode is a simple form of a semiconductor; it allows
electricity to flow in one direction only. This idea is the heart of computer chips or IC.
IC (Integrated Circuit): An integrated circuit contains thousands of components
compressed into a microscopic area. With the development of the IC, came the
development of small electronic devices. IC’s are found in cars, toys, homes, computers,
refrigerators, electronic devices & many other devices.
Binary System: A computer logic system that is base 2. The binary language is so
simple, it only consists of two words: 1 or 0 (also known as On or Off, and Yes or No).
Schematic: A schematic is an electronic blueprint. It shows where all the parts are
located and how they are connected. Below is an example of a schematic.
Switch: A switch is a gate for electricity, a switch that is “on”
allows electrons to flow, a switch that is “off” does not allow
electrons to flow. A switch is one way that we help to control
electron flow in a circuit.
A circuit breaker is a common
household item that protects a circuit
from an overload. A circuit breaker
trips preventing current from flowing
too quickly in a circuit. A fuse is
similar to a switch, but rather than tripping, it is burned out and
must be replaced. A fuse protects the wiring & the circuit from
fire & from burning up.
GFCI- A Ground Fault Circuit Interrupter AKA a GFCI monitors the amount of current
flowing from hot to neutral. If there is any imbalance, it trips the circuit. So let's say you
are outside with your power drill and it is raining. You are standing on the ground, and
since the drill is wet there is a path from the hot wire inside the drill through you to
ground. If electricity flows from hot to ground through you, it could be fatal. The GFCI
can sense the current flowing through you because not all of the current is flowing from
hot to neutral as it expects -- some of it is flowing through you to ground. As soon as the
GFCI senses that, it trips the circuit and cuts off the electricity.
Grounding- is to protect the people who use metal-encased
appliances from electric shock. The casing is connected directly to
the ground prong. If the metal-encased appliance comes in contact
with the “hot” wire, the breaker will trip creating an “open” or “off”
circuit. This protects the user from electric shock. People who cut
off the “ground” or “third” prong from an electrical cord cut off their
safety factor.
Series Circuit: In a series circuit there is a single path for electrons to flow. If there is an
“open” part of the circuit the electricity is stopped. (IE older style X-mass tree lights)
Parallel Circuit: In a parallel circuit there are multiple paths
for electrons to flow. Current
may still flow even if there is
a break in the circuit. (IE
modern X-mass tree lights.)
Ohms Law: explains the relationship between voltage, current and resistance.
V = volts
A = current (in amps)
Ω = resistance (in ohms)
Put your finger over the value that you want to find. Multiply
the remaining values if side-by-side; divide if one is over the
other.
Be able to draw the following circuits:
Open Circuit: Electrons do
not flow.
Closed Circuit: Electrons
flow.
Short Circuit: Electrons flow
uncontrolled (no work done).