Diode

Is a type of Electronic that conduct current in one direction.

Characteristics

Two pins: - Anode - The "input" or "positive side" - Marked with a white/black band, or with a long leg - Cathode - The "output"

Accompanying resistor

A Resistor is needed in series, otherwise there would be too much current. In datasheet, you need to locate: - The diode forward voltage: V_LED, V_F - The diode forward current: I_F

You can calculate with the following formula based on Ohm's Law : $$u=ri \iff r=\frac{u}{i} \iff r=\frac{V_{source}-V_{LED}}{I_{LED}}$$

Schematic