Elenco Electronics 202 - Manual (Page 108)

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Project #252 Electromagnetism
& Compass
You need a compass for this project (not included). Use the circuit
from project #251, with the iron core rod in the electromagnet (M3).
You may want to use the slide switch (S1) in place of the press switch
(S2), but only turn it on as needed or you will quickly drain your
batteries.
Turn on the switch and move the compass around near the edges of
the electromagnet, it will point toward ends of the iron core rod. By
slowly moving the compass around the electromagnet, you can see
the flow of its magnetic field.
The earth has a similar magnetic field, due to its iron core. A compass
points north because it is attracted to this magnetic field. The
electromagnet creates its own magnetic field, and attracts the
compass in a similar way.
Magnetic Field
Compass
OBJECTIVE: To learn how electricity and magnetism are
related.
Project #253
OBJECTIVE: To learn about the electromagnet.
Turn on the slide switch (S1) - nothing happens. Turn the switch off -
the LED (D1) flashes.
When you turn on the switch, the electromagnet (M3) stores energy
from the batteries (B1) into a magnetic field. When you turn off the
switch, the magnetic field collapses and the energy from it discharges
through the LED.
Electromagnet
Storing Energy