Elenco Snaptricity&reg - Manual (Page 78)

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Reed Switch (II) Project #68
Educational Corner:
Electric Paths
This circuit acts as a reed switch, which is an electrical
switch operated by a magnetic field. In this case, the
magnet uses the reed switch to control electrical and
mechanical devices (the lamps and thin rod).
Description
Set the slide switch (S5) to position B to turn on the circuit, the
top lamp (L4) should be off and the bottom lamp should be on.
Now hold the magnet about 0.1 inch above the nut-snap to
attract it, this should turn on the top lamp, turn off the
bottom lamp, and suck the thin rod into the electromagnet.
Moving the magnet up and down slightly above the nut-
snap should attract and release it, flipping the lamps on and
off and bouncing the thin rod.
Operation
Build the circuit as shown. Place paper clips at base grid
locations A7 and C7, beneath all the parts (this is used to
raise the parts slightly). Snap the 6-snap at B2, then place
it so it lays on the snap at B7 (DO NOT SNAP IT ON).
Place the nut-snap on the 6-snap. Drop the thin rod inside
the electromagnet (M3).
Assembly
Snappy says: a reed switch
could be used in a door
alarm. If a reed switch is in a
wall and a magnet is on a
door next to it, an alarm
could be triggered if the door
is opened.
N S
Paperclips