User Manual

VMP502
V. 02 – 25/10/2019 4 ©Velleman nv
6. Operation
6.1 A Blinking LED
Learn how to programme the Raspberry Pi
®
to make an LED burn.
Required Hardware
• 1 x Raspberry Pi
®
• 1 x breadboard
• 1 x LED
• 1 x 220 Ω resistor
• jumper wires as needed
A semiconductor LED is a type of component, which can turn electric energy into light energy via PN junctions.
By wavelength, it can be categorized into a laser diode, an IR LED and a visible LED.
When a 2 V to 3 V forward voltage is supplied to an LED, it will blink only if the forward currents flow through
the LED. Usually, there are red, yellow, green, blue and colour-changing LEDs. LEDs are widely used due to
their low operating voltage, low current, luminescent stability and small size.
LEDs are diodes. Hence, they have a voltage drop, which varies from 1 V to 3 V depending on their types.
Likewise, LEDs usually emit light if supplied with a 5 mA tot 30 mA current, and generally 10 ma to 20 mA is
used. When an LED is used, it is necessary to connect a current-limiting resistor to protect the LED from over-
burning.
In this experiment, connect a 220 Ω resistor to the anode of the LED, connect the resistor to a 3.3 V power
source, connect the cathode of the LED to the GPIO. Write 0 to the GPIO and the LED will blink.
Experiment