Lesson 7 – Control LED (in parallel) brightness using Resistors
Paper Circuits track I is designed to introduce you to various fundamental concepts related to electronics. Electronics is the study of how to control the flow of electrons (sub atomic particles responsible for moving energy around as we know it). Electronics essentially deals with circuits made up of components that control the flow of electricity. Electronics as a branch of science, is a part of physics and electrical engineering.
What is this tutorial about – In this tutorial we will build upon our learning gained so far. We’ll create a circuit with two LEDs, two resistors, a power source (CR2032 battery) and some copper tape. For purposes of this tutorial we will be using use the paper circuit template 4 from the Paper Circuit Track I kit. This circuit will setup the two LED’s in parallel with each other.
What do paper circuits look like –
Before we get started and create our own paper circuits lets take a few minutes and check out some of these videos to see what others have created using simple paper circuits.
Components required –
The components required for this tutorial include –
- 2 x LED or Light Emitting Diode
- 2 x Resistor
- 1 x CR2032 coin cell battery
- Copper tape
- Paper circuit template for tutorial 4
Building your paper circuit –
Step 1 – Lay everything out
For this tutorial you will need Paper Circuit template 4. Here’s what that should look like.
Before you get started lay out all your components on top of the paper circuit template and make sure you understand their orientation, placement.
Please Note – The initial version of the kit shipped with LED’s (like the one below) without markings to denote the polarity i.e. Anode/Cathode. As you would know (from our earlier tutorials) that the LED is a type of diode and only will light up when the Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the battery. If you have an LED with a dot on it, please ignore the notes in this section.
You should test out the right orientation of the LED before sticking it onto the paper circuit. One way of doing this is to layout the copper tape all along the track, setup the CR2032 battery at the bottom corner aligned with the circle and then test out the LED by placing it at the right spot (in this case right at the top). Try different orientations of the LED and confirm which one lights it up. Only one orientation of the LED will work i.e. LED will only light up when the Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the battery.
Verify that your setup looks like that shown in the picture before proceeding to the next step.
Each of the paper circuit tutorials comes with two pages, the first page is for you to add your art work and color on while the second page is to be used to create the paper circuit.
Step 2 – Laying Copper Tape
Start laying copper tape all around the track that’s been marked on the paper circuit template.
Laying copper tape across straight lines is easy but things do get tough when you need to lay copper tape around smooth or sharp corners. Laying down copper tape around sharp corners is a trick and gets easier as you gain experience. You do not have to cut the copper tape at the corner, there’s an easier way to do it. Besides cutting copper tape at sharp corners is going to make it harder for you to create a circuit that is continuous.
Have a look at the video shown below to understand how to lay copper tape around the track following through sharp corners.
Step 3 – Setup the power source using the CR2032 button cell.
- Lay the CR2032 button cell on circuit within the circle provided.
- The CR2032 button cell is laid down in such a way that one side of the button is cell is permanently on top of the copper tape.
- The second side of the CR2032 button cell only touches the other side of the copper tape when you fold the paper, acting as a switch.
- This setup ensures that power only flows through the circuit and LED lights up when you firmly press the paper with copper tape against the button cell.
Step 4 – Connect up the 2 x LED’s to the circuit including the 2 x Resistors
Before you can connect the LED’s to the circuit please make sure you’ve oriented the LED’s in the right direction.
- You should test out the right orientation of the LED before sticking it onto the paper circuit. The dot on the LED signifies the Anode while the other side of the LED is the Cathode.
- One way of doing this is to layout the copper tape all along the track, setup the CR2032 battery at the bottom corner aligned with the circle and then test out the LED by placing it at the right spot (in this case right at the top).
- Get the orientations of the LED right and confirm that it lights it up. Only one orientation of the LED will work i.e. LED will only light up when the Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the CR 2032 battery.
Once you’ve oriented the LED correctly and tested things out, peel off the white protective strip at the bottom of the LED and stick them to the paper circuit template in such a way that each of the legs of the LED touches one side of the copper tape. Unless the LED is oriented in the right direction i.e Anode (positive terminal) connects up to the Positive of the battery and the Cathode (negative terminal) connects up to the negative terminal of the battery and each of the LED’s legs are touching one side of the copper tape the circuit won’t be complete and the LED’s will not light up.
The resistor does not have any polarity as such can be fixed without worrying about orientation i.e. Anode (+ve or Positive) or Cathode (-ve or Negative) connecting to the relevant terminal of the battery. So go ahead and connect up the resistors to the circuit. Peel off the white protective strip at the bottom of the resistor and stick them to the paper circuit template in such a way that each of the legs of the Resistor touches one side of the copper tape. Unless each of the resistors legs are touching one side of the copper tape the circuit won’t be complete and current will not flow through it.
Step 5 – Testing everything out and coloring it in
If you’ve got to this point and got your circuit working give yourself a pat on the back.
You’ve successfully built your fourth electronic circuit using LED’s, a power source (CR 2023 coin cell battery) and Copper tape.
Very well done !!!
About Paper Circuits Track I –
Paper circuits are a great way to get started with the fundamentals of electronics. Simply speaking paper circuits are low voltage electronics circuits that one creates using a combination of paper, conductive copper tape, passive or active electronic components (resistors, LED’s, etc.) including an easy to access power source like a coin cell battery. Educators and parents alike are able to make use of paper circuits to help kids learn relevant fundamentals of electronics by engaging them in hands on activities. Kids create these circuits using the various components provided and through the making learn key concepts. Our paper circuits kits enables kids of all ages with the opportunity to explore fundamentals of electronics without having to worry about damaging expensive electronic boards or components or getting hurt. Paper circuits are a combination of electronics and art bringing together a blend of creativity, learning and experimentation.