Data Sheet

13 : circuit 1a
YOU
NEED
NEW COMPONENTS
LIGHT-EMITTING DIODES (LEDS) are
small lights made from a silicon diode. ey come
in dierent colors, brightnesses and sizes. LEDs
(pronounced el-ee-dees) have a positive (+) leg and
a negative (-) leg, and they will only let electricity
ow through them in one direction. LEDs can
also burn out if too much electricity ows through
them, so you should always use a resistor to limit
the current when you wire an LED into a circuit.
RESISTORS resist the ow of electricity. You
can use them to protect sensitive components like
LEDs. e strength of a resistor (measured in ohms)
is marked on the body of the resistor using small
colored bands. Each color stands for a number,
which you can look up using a resistor chart. One
can be found at the back of this book.
NEW CONCEPTS
POLARITY: Many electronics
components have polarity, meanig
electricity can (and should) ow
through them in only one direction.
Polarized components, like an LED,
have a positive and a negative leg
and only work when electricity ows
through them in one direction.
Some components, like resistors, do
not have polarity; electricity can ow
through them in either direction.
OHM’S LAW describes the
relationship between the three fundamental
elements of electricity: voltage, resistance and
current. is relationship can be represented by
this equation:
V=I•R
V = Voltage in volts
I = Current in amps
R = Resistance in ohms (Ω)
is equation is used to calculate what resistor
values are suitable to suciently limit the current
owing to the LED so that it does not get too hot
and burn out.
Circuit 1A:
Blinking an LED
You can nd LEDs in just about any source of light,
from the bulbs lighting your home to the tiny status
lights ashing on your home electronics. Blinking
an LED is the classic starting point for learning how
to program embedded electronics. It’s the “Hello,
World!” of microcontrollers. In this circuit, you’ll
write code that makes an LED blink on and o.
+–
10k
100k
330
LED  RESISTOR  JUMPER WIRES
SIK v4 Book Oct 13.indb 13 10/18/17 9:59 AM