Paper Circuits and Switches

Make a paper circuit that can be used for collages or cards!

Electricity is dangerous! Read this caution.

Materials: One sheet of paper, one or two LEDs, copper tape, one paper fastener (brass brad), a small piece of magnetic tape, a few paperclips, transparent tape, and one 3V watch battery.

Piece of paper with ~3.5 inch piece of copper tape near top-left edge (paralleling the top edge of the paper)

On a small piece of paper, place one 3.5 inch piece of copper tape near the edge (as pictured).

Small cut made in paper underneath the copper tape. The slip parallels the copper tape.

Cut a slit that parallels the piece of tape from 1/3 to 1/2 the length of the tape.

Second piece of copper tape (~3.5 inches) added underneath the slit. the second piece parallels the first.

Add another piece of copper tape underneath the slit.

An LED light is secured (~2/3 down the copper tape pieces) with transparent tape so that each lead touches one piece of copper tape.

Use transparent tape to secure the leads of an LED to each piece of copper tape. Remember which side is positive and negative.

A 3V battery is added to the left edge of the second piece of copper tape (below the slit)

Place the correct battery pole on the bottom "wire" and fold the flap over to connect the upper pole.

The top piece of copper tape is folded over the battery and secured with a paperclip. The LED light shines.

Secure the battery with a paperclip.

With the first LED lit, a second LED is added near the right end of the copper tape pieces (in parallel to the first LED). The second LED also lights!

Add another LED

Place another LED near the first. Be sure the positive lead (anode) of each LED is placed on the same piece of copper tape or it will not function.

Click to Read What's Happening

Atoms are composed of a nucleus of protons and neutrons surrounded by electrons in various clouds/shells. Most often, the number of protons equal the number of electrons. However, the placement of some electrons in these shells/clouds allows them to leave more easily. These free electrons can flow to atoms nearby, thus making them negatively charged. Normally, the exchange of these electrons happens in random order. However, when a voltage is applied to these materials, it allows the electrons to flow through the material in a particular direction, known as current.

Some materials allow this flow of electrons more easily than others. Those materials that allow electricity to flow through them more easily are called conductors. Those that don’t allow electricity to flow through them easily are called insulators. Examples of conductors include copper, aluminum, gold, and silver. Examples of Insulators include plastic, rubber, paper, ceramics, and glass.

Circuits

Because some materials allow electricity to flow through them more easily than others, they are used to form electric circuits. A circuit is a closed circle (or path) that electric current can flow through. The circuit begins at the power source (in this case, a battery), flows through wires (our copper tape) and loads (e.g., LEDs) and back to the battery. Electricity will only flow if a complete circle is made--the path begins and ends at the power source. See this video for another example: https://youtu.be/VnnpLaKsqGU


Add a Switch!

Two 1/4 inch nibs of magnet tape are secured about an inch apart to the top-center of a piece of paper.

Cut two small ~1/4 inch square nibs of magnetic tape. Remove the tape backing and place them so they have an ~1 inch gap between them.

A piece of copper tape is placed on top the left magnetic nib and continues (parallel to the top of the paper) to the left until it gets near the left edge of the paper. This processes is reversed (everything going to the right) for the right nib.

Beginning on each magnetic nib, add a piece of copper tape so the gap remains.

About an inch underneath the first two copper tape pieces, an additional piece of copper tape is placed that runs the entire length (left to right) of the paper parallel the top pieces of tape.

Add another piece of copper tape underneath the first two.

A slit is made on the left side of the paper inbetween the two pieces of copper tape. An LED light is also placed on the far right pieces of tape with one lead on the top piece and another on the bottom.

Add your LED (considering polarity). Then cut a slit between your copper tape wires. to allow for folding the top wire over the bottom. If desired remove part of the bottom wire to facilitate binder clip (or paperclip) placement to secure the battery.

A paperclip is added to bridge the gap between the two magnets on the top sections of tape.

Add a paperclip to the gap. The magnets should secure it in place.

A batter is added to the bottom-left piece of tape, the top piece of tape is folded over to touch the top of the battery and secured with a binder or paperclip. The LED lights.

Secure the battery. Your LED should light. If it doesn't, check your battery, secure your connections, and consider the polarity of your LED.

If the paperclip is removed, the LED does not light up.

Moving the paperclip will create a gap in your circuit, preventing current from flowing from the battery, through the LED, and back to the battery.

Click to Read What's Happening

A closed circuit is a complete circuit where electricity can flow (beginning at the power source and returning to the power source). An open circuit is an incomplete circuit where a gap in the path exists. This gap prevents electricity from flowing to and from the battery (and any loads).

This gap is usually caused by an open switch or button. Notice that when you open your switch, a gap in the circuit appears and electricity cannot flow. When you close your switch, the gap is bridged by the paperclip. In reality, you have two switches in this circuit. One switch connects both poles of your battery. The second connects the wire.


Other Switches

The magnetic switch is one of the easiest and most reliable switches available. The magnets ensure that switch components complete the circuit by pressing against copper tape wires. However, switches come in many forms. You can make other types of switches depending on your project (or materials available to you). Below are instructions for a button-like switch (pressing circuit components together with a piece of copper tape mounted on a piece of paper). Instructions are also provided for a knob-like switch that uses a paper fastener.

Two pieces of copper tape parallel the top of a piece of paper (with an inch gap midway between them). A small slit has been made underneath the left piece of tape so it can fold.

Begin as you did with the previous card. However, make a small gap in the first piece of copper tape.

The left piece of tape has been folded over so it touches the paper beneath it.

Create the slit that parallels the tape and fold it over to see where the next piece of tape needs to be located.

A second piece of copper tape was placed underneath the slit to parallel the first two. It spans the entire length of the paper. An LED light is secured with transparent tape at the right side (one lead on the top and bottom pieces of copper tape).

Place the next piece of copper tape below the slit and secure the LED leads with transparent tape.

The circuit was flipped over and a small piece of paper has been secured to the back with tape so that it extends ~2-3 inches above the first piece of paper. It is positioned to bridge the gap on the top pieces of copper tape.

Cut a piece of paper that is wider than your gap in the copper tape. Use transparent tape to secure it to the back side of the larger paper (so it can fold over your circuit).

The circuit was flipped right-side up again and the extra paper was folded over it to cover the gap.

Fold the extra piece of paper so that it covers your gap in first piece of copper tape.

A pencil marks indicates where the piece of paper bridges the gap in the circuit.

With the extra piece folded over the gap, use a pencil to mark the position of the circuit.

A piece of copper tape was placed on the underside of the folded paper bridging the gap so that when pressed, the copper tape on the extra paper will close the gap.

Unfold the flap and position copper tape along the extra piece of paper so it will touch the copper tape on both sides of the gap when closed.

A 3V coin battery is placed on the far left of the bottom piece of copper tape.

Place your battery on the bottom piece of copper tape.

The top piece of copper tape is folded over the battery and secured with a paperclip

Fold over the battery connection flap and secure it with a paperclip. The gap in your circuit prevents the LED from lighting.

Two fingers press the extra flap of paper to close the gap between the top side of copper tape. This flap acts as a button and completes the circuit. The LED lights.

Fold over the flap to complete your circuit and light the LED.


If your LED still doesn't light, Troubleshoot.

  • Does the battery have power?

  • Make sure your components and battery are touching the appropriate wires.

  • Do you have any shorts (where positive wires are touching negative wires?

Knob (Rotational) Switch

One piece of copper tape spans the top of a piece of paper (from left to right)

Begin as you did in the previous activities.

An ~2 inch slit is added underneath the left edge of the piece of copper tape. Two additional pieces of tape are added underneat the first with a gap between them. An LED light is secured with tape at the far end of the circuit (one lead on the top and the other on the bottom piece of copper tape.

Make a gap in the copper tape that is smaller than the width of a paper fastener prongs when they are extended. Secure the LED with transparent tape

The paper is turned over and a paper fastender is poked through so it's prongs extend onto the circuit.

Turn the paper over and press a paper fastener (aligned with the copper tape) midway through the gap.

The circuit is shown with prongs from the paper fastener bridging the gap between the lower pieces of copper tape.

Turn the paper over again and spread the paper fastener prongs apart so they touch the copper tape wire.

The battery is placed on the bottom-left piece of copper tape, the top piece is folded over and secured with a paperclip.

Secure the battery to the wires with a paperclip. Your LED should light.

The LED lights when the fastener prongs bridge the gap of the lower pieces of copper tape. However, a finger is pressed on the prongs to secure the connection.

If your LED doesn't light, you may try pressing the prongs onto the copper tape. If you move the switch by rotating the paper fastener, the circuit will open (causing a gap).

A tree drawn with crayon and lit up with an LED light underneath a picture of a bush.

Challenge

Using the principles learned in this activity, make a collage or card that lights up. Hide your circuit on the backside of the picture or use decorated paper cutouts to cover your circuit.

The circuit components underneath the bush image are depicted. A rotating switch is present with a paper fastener.