Ohm's Law
states that for a conductor maintained at a constant temperature,
the voltage V
across it
is proportional to the current I flowing through it. The constant
of proportionality is known as the resistance R
of the conductor. Thus, V = R x I. Ohm's Law is more
commonly written as
V = IR.
Figure 1.
Ohm's Law
Consequently,
the current I flowing through a resistor when a voltage V is applied
across it may be calculated using Ohm's Law:
I = V/R
where R is the resistance of the resistor. If a current I is
forced to flow through a resistor with resistance R, the voltage drop V
across the resistor would be equal to V = I x R. If a voltage V is
applied across a resistor of unknown resistance and this applied voltage
causes a current I to flow through it, then the resistance R of the
resistor is given by:
R = V/I.
Ohm's Law
applies not just to a single resistor (a component exhibiting resistance), but to entire circuits consisting of many resistors
connected in various ways. A complex circuit of resistors
connected in any manner and across which a voltage V is applied may be
mathematically analyzed as a single equivalent resistor Reff, through
which a current I is made to flow by the applied voltage V. Ohm's Law
may be applied to this equivalent resistor, i.e., V = IReff, where V is
the voltage applied across the circuit and I is the current consumed by
the circuit.
See Also:
Resistance
