YOUR OWN ELECTRO-BOARD
ELECTRO-SCIENCE IS MORE THAN BATTERIES, WIRES AND BULBS. SCIENTISTS
HAVE BASIC PIECES OF EQUIPMENT THEY USE MANY TIMES IN THEIR EXPERIMENTS.
THE ELECTRO-BOARD IS AND IMPORTANT TOOL. IT LOOKS COMPLICATED, BUT IT IS
EASY TO PUT TOGETHER. HERE'S HOW.
- 1 piece of soft wood, 16 cm x 7.5 cm x 2 cm
- 5 short screws (#6 x 3/8 self tapping)
- 4 Fahnestock clips
- 1 battery holder
- 1 snap connector for battery holder
- an LED
- 1 33 ohm resistor
- 2 AA batteries
- 1 paper card 2 cm x 8 cm
- 20 gauge wire
- a wire stripper/cutter
- a screwdriver
- a straight pin
- a black magic marker
Follow these steps. The pictures will help you.
- Make 4 pairs of evenly spaced pinholes down the centre of the card.
Mount the LED by pushing its wires through the first pin hole. These wires
must not be touching. Use the marker to label the LED 1.
- Place the card on the right end of the board
- Bend the + wire out one side. Put a big + sign on the board above the
- Bend the - wire out the other side. Put a big - sign on the board below
- Place one Fahnestock clip on each side.
- Slide the end of a wire under each clip and use screws to attach them
to the board.
- Snap batteries into the holder and attach the snap connector. Tape
the holder down on the end of the board.
- Attach the wire at one end of the resistor and the bare end of the
black wire both to the board with the same screw.
- Use another screw and a Fahnestock clip to fasten the other end of
the resistor down. Put them on the same side of the board as the - LED
wire. Label this clip with a B.
- Now, use a screw and Fahnestock clip to attach the bare end of the
red wire to the + side of the board. Label this clip A.
HERE IT IS — YOUR ELECTRO-BOARD!
Finally, test it. Experiments and scientists always check out their
- Cut two short wires and bare the ends. Attach one end of each to these
Fahnestock clips. That connects them to the battery.
- Now, place the free end of each wire into the two clips for the LED
to check your circuit. It should glow as you complete its circuit. If not,
make sure that the batteries are sitting properly in the holder, that everything
is connected and that the LED is in the right way.
This project results in a handy tool that assembles and holds a collection
of electrical components. The electro-board is a necessary part of most
of the activities that follow. The wood block only has to hold everything
in place. its size and shape are not important. The paper card is a holder
for the LED. Since there will be three more, spread the pin holes down
the card so that the LEDs will be evenly spaced out.
The resistor increases the life of batteries by reducing the flow of
electrons to the LEDs. It also prevents heating if you accidentally create
a short circuit.
The resistor must be used to reduce the flow of electrons to the LED.
LEDs are easily destroyed if too many electrons are allowed to flow. Use
two AA batteries only, otherwise LEDs would likely burn out. LEDs come
in many shapes and sizes. If you want to try out some different ones, get
Sometimes it is difficult to tell which LED wire is "+" and
which one is "-". If so, trial and error works because it lights
only when it is connected correctly. Also "-" is from the battery
and "+" is to the battery. Start the holes in the board with
a nail to help the screws go in easier.
Students should have had the opportunity to practice with wire strippers.
They need to learn how to remove the insulation without cutting through
the wire. Electrons can flow either way through a resistor, so it doesn't
matter which way around it is connected.
Snap connectors have colour coded wires. Red is "+". Black
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