Miyerkules, Oktubre 12

Fundamentals of Electricity

Analogy of Voltage, Current and Resistance.

Voltage

Voltage is the electrical force that moves electrons through a conductor. Voltage is electrical pressure also known as EMF (Electro Motive Force) that pushes electrons. The greater the difference in electrical potential push (difference between positive and negative), the greater the voltage force potential.

Current

Electric current is a flow of electric charge through a medium. This charge is typically carried by moving electrons in a conductor such as wire. It can also be carried by ions in an electrolyte, or by both ions and electrons in a plasma.

Flow of electrons (current) in the conductor has the following effects: USEFUL & DETRIMENTAL

1. If enough current flows across the filament of a bulb, it will illuminate to produce light
2. High current flow in the coil produces heat and used as a heater
3. High current flow in the electrical conductor produces heat that might damage the insulator

The higher the current flow, the greater the heat generated.

Electromagnetism

Magnetic effects generate in the flow of electrons. Same principle is used in motors, solenoid, buzzer, and other actuator in a control system.

The strength of the magnetic field around the coil can be increased by:

1. Using a soft iron core (core means middle bit)
2. Using more turns of wire on the coil
3. Using a bigger current

Wrapping the wire in a coil concentrates and increases the magnetic field, because the additive effect of each turn of the wire.

Resistance

The electrical resistance of an electrical element measures its opposition to the passage of an electric current; the inverse quantity is electrical conductance, measuring how easily electricity flows along a certain path. Electrical resistance shares some conceptual parallels with the mechanical notion of friction. The SI unit of electrical resistance is the ohm (Ω).

Resistance is the force that reduces the flow of electrons. Higher resistance decrease the flow of electrons and lower resistance allow electrons to flow freely.

Big Conductor = Low Resistance
Small Conductor = High Resistance

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