LED Circuit

In electronics, the basic LED circuit is an electric power circuit used to power a light-emitting diode or LED. The simplest such circuit consists of a voltage source and two components connected in series: a current-limiting resistor (sometimes called the ballast resistor), and an LED. Optionally, a switch may be introduced to open and close the circuit. The switch may be replaced with another component or circuit to form a continuity tester.

(Although simple, this circuit is not necessarily the most energy efficient circuit to drive an LED, since energy is lost in the resistor. More complicated circuits may be used to improve energy efficiency).

The LED used will have a voltage drop, specified at the intended operating current. Ohm's law and Kirchhoff's circuit laws are used to calculate the resistor that is used to attain the correct current. The resistor value is computed by subtracting the LED voltage drop from the supply voltage, and then dividing by the desired LED operating current. If the supply voltage is equal to the LED's voltage drop, no resistor is needed.

This basic circuit is used in a wide range of applications, including many consumer appliances.

Famous quotes containing the words led and/or circuit:

“We crossed a deep and wide bay which makes eastward north of Kineo, leaving an island on our left, and keeping to the eastern side of the lake. This way or that led to some Tomhegan or Socatarian stream, up which the Indian had hunted, and whither I longed to go. The last name, however, had a bogus sound, too much like sectarian for me, as if a missionary had tampered with it; but I knew that the Indians were very liberal. I think I should have inclined to the Tomhegan first.”
—Henry David Thoreau (1817–1862)

“The Father and His angelic hierarchy
That made the magnitude and glory there
Stood in the circuit of a needle’s eye.”
—William Butler Yeats (1865–1939)