Why is Ohms law important in the electrical field?

Answer 1

Ohms law "V= RI" is the " F=ma or Newton's Law" of Electricity. It gives the quantitative relationship between the three important concepts of electricity, V=Voltage, I= Current and R= Resistance.

Answer

Ohm's Law is not really important at all, as it is not universal and applies to very few conductors and, then, only under very strict conditions. For a circuit to obey Ohm's Law, its ratio of voltage to current must remain constant for variations in voltage, and this is rarely the case! Most conductors, and most electric devices such as diodes, etc., simply do not obey Ohm's Law. In fact, some engineers and scientists would argue that Ohm's 'Law' should not be a law at all as it applies in so few circumstances.

The problem is that many people, including many electricians, mistakenly think that Ohm's Law is represented by an equation that tells us the resistance is voltage divided by current whereas, in fact, this equation is derived from the definition of the ohm, and NOT from Ohm's Law.

Answer 2

Ohm's Law states that 'the current flowing in a conductor, at constant temperature, is proportional to the potential difference across its ends'.

Ohm's Law is not universal, and only applies to materials that are linear or ohmic, that is materials in which the ratio of voltage to current is a constant for changes in voltage. In other words, it only applies when there is a straight-line relationship between current and voltage. This applies to most, but not all, metal conductors.

Ohm's Law does not apply to materials that are non-linear or non-ohmic, that is materials in which the ratio of voltage to current varies with changes in voltage. In other words, if there is a curved-graph relationship between current and voltage. Some metals, such as tungsten, are non-linear, as are electrolytes, gases, and semiconductor devices such as diodes.

In fact, Ohm's Law does not apply to most conduction materials!

However, the ratio of current to voltage (which is resistance) will always tell you what the resistance happens to be for that particular ratio, whether Ohm's Law applies or not.

The equation, R = V/I, does notrepresent Ohm's Law; it is derived from the definition of the ohm. This is a major misconception about Ohm's Law perpetuated by science teachers without formal qualifications in science.

Answer 3

Ohm's law states voltage is equivalent to current times resistance. It's a law, and is applicable to any electrical device.

Answer

Ohm's Law is not a universal law; in fact, it hardly qualifies as a law at all. This is because it doesn't apply to most loads.

For Ohm's Law to apply, the ratio of voltage to current must remain constant for variations in voltage. In other words, if you were to plot a graph of current against voltage, for variations in voltage, the result must be a straight line. Hardly any conductors, and practically no semiconducting devices, will produce a straight-line graph. For example, if you were to plot current against voltage, for variations in voltage, for a tungsten filament, the result would be a curve -demonstrating that tungsten does not obey Ohm's Law. In fact the only time most metals obey Ohm's Law is if their temperatures remain constant which, of course, they do not if larger currents flow through them.

It's time we stopped teaching Ohm's Law!

Answer 4

First of all, 'electricity', is the name given to a branch of science; it is NOT a quantity that can be measured, such as voltage, current, etc.

Secondly, Ohm's Law does NOT 'affect electricity'. It's the other way around! It merely describes how 'electricity' behaves; it doesn't determine how 'electricity' behaves!

Thirdly, Ohm's Law is not a universal law, and only applies to very few materials or electrical components. In fact, it could be argued that Ohm's Law isn't a 'law' at all because it applies in so few circumstances.

Ohm's Law states that the current passing through a conductor is proportional to the potential difference appearing across that conductor... providing various physical conditions, such as temperature, remain constant. But, unfortunately, this is not true in most practical circumstances.

Frequently, too, Ohm's Law is credited with the equation, R = U/I; again, this is not the case, because this equation is derived from the definition of the ohm, not from Ohm's Law.

There is a really serious case for scrapping Ohm's Law altogether!

Answer 5

Ohms Law is used to describe the behaviour of components in, and the behaviour of the whole circuit.