Question
Tue May 01, 2012 By:

Why does electricity pass when resistance opposes the flow of electrons?is electricity regulated by flow of electrons?

Expert Reply
Tue May 01, 2012

Resistance:

Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must dropped (used) across the conductor (wire). Resistance can be described by ohms law:

Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms)

where:

Voltage [V]= the energy lost across an component (voltage measured in volts).

Current [I] = the charge (electrons) flowing through an component (current measured in Amps).

Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your steady.

When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen the electrical resistance plays a large role in modern life.

Resistor:

The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependant on the amount of power passing through the resistor, given by:

P = V x I (Power = Voltage x Current) (power measured in watts)

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