Elenco Snaptricity® - Manual (Page 72)

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Relay Project #62
Educational Corner:
When you need a relay for a circuit, you usually buy
one instead of building one.
FOR ADVANCED USERS - ADULT SUPERVISION RECOMMENDED
Electric Paths
Relays are electronically controlled switches,
which allow a low-voltage circuit to control a
high-voltage or high-current circuit. You may
never have heard of them, but they are used in
many appliances in your home.
Electrical Symbol for Relay Actual Relay
This circuit is a relay , which uses one circuit to create a magnetic field
that controls another circuit. The current through the electromagnet
makes a magnetic field that attracts the nut-snap, which breaks the
circuit to the lamp.
Description
Turn on the slide switch (S5, position C). The lamp (L4) should be on (if off,
make sure the 4-snap is touching the 2-snap at D2 without being snapped there).
Push the press switch (S2) to turn on the electromagnet. This should raise
the 4-snap slightly and turn off the lamp (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 B4 to the proper spring direction as shown, this may make the
4-snap move more easily.
Operation
Build the circuit shown. Three 3-snaps are stacked together at base grid
location D3-F3. Snap the 4-snap onto the 1-snap at B4, then place it so
it lays on the snap at D2 (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