1. 5/8/2015 Electrical circuit - Simple English Wikipedia, the free encyclopedia
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A simple electrical circuit. This circuit
has a power source, a complete path
for electrons to flow, and a resistor
as the load.
Electrical circuit
From Wikipedia, the free encyclopedia
An electric circuit is a path in which electrons from a voltage or current
source flow. Electric current flows in a closed path called an electric
circuit. The point where those electrons enter an electrical circuit is called
the "source" of electrons. The point where the electrons leave an
electrical circuit is called the "return" or "earth ground". The exit point is
called the "return" because electrons always end up at the source when
they complete the path of an electrical circuit.
The part of an electrical circuit that is between the electrons' starting point
and the point where they return to the source is called an electrical
circuit's "load". The load of an electrical circuit may be as simple as those
that power electrical appliances like refrigerators, televisions, or lamps or
more complicated, such as the load on the output of a hydroelectric
power generating station.
Circuits use two forms of electrical power: alternating current (AC) and direct current (DC). AC often powers large
appliances and motors and is generated by power stations. DC powers battery operated vehicles and other
machines and electronics. Converters can change AC to DC and vice versa. High-voltage direct current
transmission uses very big converters.
Contents
1 Electronic circuits
2 Circuit and wiring diagrams
3 Circuit breakers
4 Ground-fault-interrupt (GFI) devices
5 Other websites
Electronic circuits
Electronic circuits usually use low voltage direct current sources. The load of an electronic circuit may be as simple
as a few resistors, capacitors, and a lamp, all connected together to create the flash in a camera. Or an electronic
circuit can be complicated, connecting thousands of resistors, capacitors, and transistors. It may be an integrated
circuit such as the microprocessor in a computer.
Circuit and wiring diagrams
Electrical and electronic circuits can be complicated. Making a drawing of the connections to all the component
parts in the circuit's load makes it easier to understand how circuit components are connected. Drawings for
electronic circuits are called "circuit diagrams". Drawings for electrical circuits are called "wiring diagrams". Circuit

2. 5/8/2015 Electrical circuit - Simple English Wikipedia, the free encyclopedia
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diagrams and wiring diagrams are usually drawn by skilled draftsmen, and then printed. Circuit diagrams may also
be created digitally using specialised software.
Wiring and circuit diagrams use special symbols recognized by everyone who uses the drawings. The symbols on
the drawings show how components like resistors, capacitors, inductors, motors, outlet boxes, lights, switches, and
other electrical and electronic components are connected together. The diagrams are a big help when workers try
to find out why a circuit does not work correctly.
Resistors and other circuit elements can be connected in series or in parallel. Resistance in series circuits is the sum
of the resistances.
Circuit breakers
The current flowing in an electrical or electronic circuit can suddenly increase when a component part fails. This can
cause serious damage to other components in the circuit, or create a fire hazard. To protect against this, a fuse or a
device called a "circuit breaker" can be wired into a circuit. The circuit breaker will open, or "break", the circuit
when the current in that circuit becomes too high, or the fuse will "blow". This gives protection.
Ground-fault-interrupt (GFI) devices
The standard return for electrical and electronic circuits is the earth ground. When an improperly designed electrical
or electronic device fails, it may open the return circuit to the earth ground. The user of the device could become a
part of the device's electrical circuit by providing a return path for the electrons through the user's body instead of
the circuit's earth ground. When our body becomes part of an electrical circuit, the user can be seriously shocked,
or even killed by electrocution.
To prevent the danger of electrical shock and the possibility of electrocution, ground fault interrupt devices detect
open circuits to earth ground in attached electrical or electronic devices. When an open circuit to earth ground is
detected, the GFI device immediately opens the voltage source to the device. GFI devices are similar to circuit
breakers, but are designed to protect humans rather than circuit component.
Other websites
All About Circuits (http://www.allaboutcircuits.com)
Media related to electric circuits at Wikimedia Commons
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Category: Electricity
This page was last changed on 6 May 2015, at 19:57.
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