## Teach basic concepts in electricity

I was providing support at a school campus when I was asked by a teacher to help with an interactive display board. I noticed she was teaching a lesson on basic circuits using a light bulb, switch, and battery. The lesson was going well but some light bulbs didn’t work and some batteries were drained. The kit was obviously old and needed updating.

I pulled the teacher aside and demonstrated Tinkercad Circuit simulator. I demonstrated how to build the same circuit in a few minutes and how to test the circuit. She was immediately sold on the simulator. We took the students to the site, they logged in with their Google account and started assembling their circuit.

It was at this time that I realized I needed to revisit Tinkercad. I wrote an issue on Tinkercad for electronics back in April of 2018. The issue covered the basic blinking LED and Arduino integration. I felt there was a need to develop another issue which covered some of the basics in a little more detail.

This issue reviews the assembly of a basic circuit with an LED and push button. We compare the use of a push button and a switch in the same circuit. The lesson emphasizes how closed circuits work and the flow of current through a circuit. The circuit uses a resistor to limit the amount of current flowing through the LED. The resistor demonstrates how we limit the flow of current through a circuit. Students understand that current is something that flows through a circuit event if we can’t see it flowing. There is an animation below that shows how current flows through our basic LED circuit. I used an app to create the circuit simulator.

In the next lesson, we assemble a circuit with a capacitor. A capacitor stores energy much like a battery. This energy is the potential energy that is released as current and kinetic energy. The purpose of the lesson is to demonstrate how energy is stored and released.

The third lesson focuses on the transistor as a switch. Transistors are commonly used in computers. This lesson uses a common transistor to light an LED. The lesson is divided into two parts. The first part uses one power source to trigger the transistor and light the LED. The second part uses two power sources. A low power source of 1.5 volts is used to trigger the transistor. A second power source of 6-volts is used to light the LED. The LED in the second part is much brighter because of the second power source. Students understand that closed circuits are formed with closed loops using physical and electronic switches.

Tinkercad is an online development tool for 3D models. It is also a development tool for circuits. The development environment is easier to use than similar tools used by professionals. It’s intuitive for students to use. The lessons in this issue will focus on the electronic circuit development environment. This environment has components to construct a variety of electronic circuits. We can assemble and test these circuits inside the development environment.

There are many benefits to using an online development and simulation environment. The service is available online so there is nothing to install. The computer should have the latest browser installed. There is no specific browser requirement. The service is free. The components don’t break. We are free to make mistakes. The environment is safe. We don’t have to worry about students sticking themselves with the points of LEDs or transistors. No electronic shock from the battery current.

A drawback is that the development and testing environment is digital. Studies show time and again the importance of kinesthetics. Kinesthetic learning is where students interact with learning by touching and interacting with objects. Students are engaged in active learning. In my experience, students learn better when they interact with the content. Using an online simulation is not enough. The online skills don’t always transfer from the simulated world to the real world. There are lots of reasons for this and one reason is the lack of context. Learning skills must be applied to real-world situations. There needs to be a connection to real-world situations and problems.

I recommend combining the online development of circuits with actual hands-on using real components and circuits. Electronic circuits are relatively inexpensive. A box of 300 LEDs on Amazon costs as little as \$9 US dollars. A box of over 500 resistors costs about the same. An assortment of capacitors costs about \$13 dollars. A pack of six mini breadboards runs about \$5.

Find an old radio in a second-hand store and open the back. Expose the electric components. Don’t plug the radio to a power source when doing this. Remove any batteries too. Identify the components and discuss their purpose.

Studying the components in a circuit ties in very nicely when discussing systems. How do the components contribute to the functioning of the radio? How would the removal of one component affection the functions of the radio? How is this similar to other systems?

#### Basic LED Circuit

The basic LED circuit is my favorite when introducing any project to teachers and students. It provides a good introduction to the basic layout and components in Tinkercad. The circuit is simple and familiar to most people.

Basic and advanced components are located in the right panel. Some of the basic components include LEDs, switches, batteries, and resistors. They form the basis of a simple LED light switch. LED stands for Light Emitting Diode. A diode is a component that permits current to flow in only one direction. Current flowing through an LED emits light

#### Capacitors

We’re going to build on the skills we learned in the LED circuit. This circuit includes a capacitor. A capacitor stores current and releases it at a steady rate. The current in a circuit can change with power fluctuations. Power fluctuations can damage sensitive circuits. They are often used to smooth out the current supplied to components. They are also used to gradually reduce the amount of current being supplied to a component.

A capacitor is a lot like a battery. It stores current and releases that current when a circuit is closed. They don’t store as much current like a battery. Capacitors are reliable and don’t need to be replaced like batteries.

Transistors and LEDs have revolutionized our modern world. Transistors have made fast and small computer possible. LEDs have made high-quality lightweight displays possible. All modern televisions and computer monitors use LEDs.

In these lessons, we will learn to use the transistor as a switch. Transistors inside computers process lots of information. The transistor we will use here is much larger than the one used in the Central Processing Unit of a computer. This transistor is used to control components.

#### Transistors as Switches

Transistors have three leads. Each lead has a name and a purpose. The center lead is called the Base. The leads on either side are called the Collector and Emitter. The location of the emitter and collector depend on the type of transistor being used. There are two types of transistors. Each transistor is referred to as either a PNP or NPN transistor.

The difference in the type of transistor depends on how it is manufactured. They are both manufactured from three layers of semiconductor material. The materials are similar to those used in diodes. A transistor is a diode with an extra layer.

The NPN transistor is the most popular and common. Each end of the transistor is made of a semiconductor material that is saturated with electrons. The center material is depleted of electrons. This positively charged layer is sandwiched between two negatively charged layers. This is the transistor we will use in our lesson.

The PNP transistor is not as common. This transistor has a negatively charged layer sandwiched between two positively charged semiconductors.

For the transistor to work as a switch the base must receive electric current. The current stimulates the base to allow the flow of current across the collector and emitter. We typically have two power sources for a circuit with transistors. One power source activates the base and another provides power for a component. Our first project will have one power source. The first project will help us compare how the second project with two power sources differs and the advantages of having two power sources.