Ohm’s Law 101
Through experiments circa 1828, George Simon Ohm determined that the amount of current, symbol is I, in a circuit depends on its resistance, symbol is R , and the line voltage V.
Hence Ohm’s Law states, I = V/R
If any two of the variables I, V, R are known, the third can be calculated.
Note that a low voltage value with a low resistance level will produce a large current flow. And with a high voltage value, the current flow can be low if there is a large level of resistance in the circuit.
The three forms of Ohm’s law are I = V/R; V = I x R; R = V/I
Additionally, according to Ohm’s Law, the amount of power consumed in a circuit is the product of current and voltage.
P = V x I
Similarly, if any two of the variables P, I, V are known, the third can be calculated.
These relationships apply to both alternating and direct current:
One ampere is the current flow produced by one volt of potential difference across one ohm of resistance level.
|Practical Units of Electricity|
|6.25 x 1018 electrons||Coulomb / second||Joule / coulomb||Joule / second||Volt / Amepere||Ampere / volt|
Units of measurement: I - amperes (amps), V - volts, R - ohms, P - watts
|Basic Unit Prefixes|
|micro||µ||0.000,001 = 1 x 10-6|
|milli||m||1,000 = 1 x 10-3|
|kilo||k||1,000 = 1 x 103|
|mega||M||1,000,000 = 1 x 106|