User Manual

11
Required parts: 9V battery*, 1000 ohm resistor (brown black red ), red LED,
push-button
How it works: As long as the push button is
pressed, a closed circuit is formed that makes the
current ow and the LED lights up.
Current ows from the (+) of the battery to the push-
button, resistor, (+) of the LED and via the (-) of the
LED back to the battery.
Using a 1000ohm resistor the current will be about
0.007A (7mA).
Time to experiment:
What happens when you swap (+) and (-) of the led?
What happens when you replace the 1000 ohm resistor with a
100K ohm resistor (brown black yellow gold) ?
Calculation of the resistor:
resistor = battery voltage – LED voltage
LED current
resistor = 9V - 1,8V = 1000ohm
0,007