How LEDs work: Difference between revisions

Line 12:

LEDs have a direction. Here's how you can tell. In the symbol at bottom left, the triangle/vertical line is the symbol for any diode. The triangle points in the direction of current flow (anode to cathode), and the line represents the band found on the body of many diodes on the cathode side.

[[image:led.png|~~150px~~]]

[[image:led.png|200px]]

The anode (+ terminal) and cathode (- terminal) are shown with respect to the flat side of the plastic housing. The flat side corresponds to the cathode. If the LED is too small (very tiny surface mount components, for example) there won't be any physical shape to the LED, but there's usually some marking to indicate the cathode side, such as a dot or a notch.

Note that the anode is typically the longer of the two legs. Just be sure to include the resistor, as shown in the little picture in the calculator, and you're good to go. It can go either "in front" or "behind" the resistor, that is to say as long as it's in the circuit it doesn't care if it's on the + or - side of the LED.

@@ Line 12: / Line 12: @@
 LEDs have a direction. Here's how you can tell. In the symbol at bottom left, the triangle/vertical line is the symbol for any diode. The triangle points in the direction of current flow (anode to cathode), and the line represents the band found on the body of many diodes on the cathode side.
-[[image:led.png|150px]]
+[[image:led.png|200px]]
 The anode (+ terminal) and cathode (- terminal) are shown with respect to the flat side of the plastic housing. The flat side corresponds to the cathode. If the LED is too small (very tiny surface mount components, for example) there won't be any physical shape to the LED, but there's usually some marking to indicate the cathode side, such as a dot or a notch.
 Note that the anode is typically the longer of the two legs. Just be sure to include the resistor, as shown in the little picture in the calculator, and you're good to go. It can go either "in front" or "behind" the resistor, that is to say as long as it's in the circuit it doesn't care if it's on the + or - side of the LED.