Elenco Snaptricity® - Manual (Page 74)

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Relay (III) Project #64
Educational Corner:
Most home appliances operate at
120V. However, the electronic
circuits used to control them
(either automatically or by
interfacing with people) operate
at lower voltages (usually 5-15V).
Relays allow these low voltage
circuits to control high voltage
machinery and appliances.
Electric
Paths
In a relay, the controlling signal and the
signal being switched do not affect each
other. This is done by using magnetism
to open or close a mechanical switch.
FOR ADVANCED USERS -
ADULT SUPERVISION RECOMMENDED
This circuit is a variation of the preceding relay circuits.The
current through the electromagnet makes a magnetic field
that attracts the nut-snap, which breaks the circuit to the
lamp. Switch Y turns on the circuit and switch X controls
the electromagnet.
Description
Set the left slide switch (“X”) to position C and the right
slide switch (“Y”) to position C. Lamps B and C should be
on (if off, make sure the 4-snap is touching the lamp snap
at D3 without being snapped there).
Set the left slide switch (X) to position B to turn on the
electromagnet. This should raise the 4-snap slightly, turn off
lamp B, and turn on lamp A (adjust the position of the grommet
on the rod if it does not). If you still can’t get it to work, rotate
the 1-snap at location B5 to the proper spring direction as
shown, this may make the 4-snap move more easily.
Operation
Build the circuit shown. At base grid location C1-C3, 3-
snaps are on levels 1 and 3 and a 2-snap is on level 4. Snap
the 4-snap onto the 1-snap at B5, then place it so it lays on
the snap at D3 (DO NOT SNAP IT ON). Place the nut-snap
on the 4-snap so it will be under the electromagnet (M3).
This circuit works best with new alkaline batteries.
Place the rubber grommet on the iron core rod and push
the rod into the electromagnet until it is just barely above
the nut-snap without touching it (0.025 inches).
Assembly
Note spring
direction of
1-snap