What is a Simple Circuit?

In electronics, a circuit is a complete path through which electrical charges can flow. A simple circuit contains at least these three components that will always be present in any circuit :

A power source is where the energy is supplied to the circuit. This is in the form of a voltage that travels through the electrical conductor, often time wires, that pushes the current to a load to be consumed. The load is any component that consumes electric power and transforms it into another form of energy- this can include heat, motion, light, and more.

To put it simply the power supply will convert some type of energy into electrical. The electrical conductor is made up of material that electric charges can move through and a load is a device that uses electrical energy.  

By definition a short circuit is the bare minimum amount of components needed to make a trip from a high potential voltage source to a low potential voltage source without shorting. This means there must be at least one load on the circuit to dissipate some of that energy. In this case, our load is the light bulb- anything that can turn current into a different form of energy is a load. 

Circuit States

A simple circuit can be in one of two states:

Open Circuit: (switch in the off position) The pathway for electrons to flow is broken and no power will be transferred to the load. 

Closed Circuit: (Switch in the on position) The pathway for electrons to flow is complete and power will be transferred to the load.

Switches are devices that change the path of the flow of electricity in a circuit. They do not count as a load because typical switches do not consume or change energy- they simply allow it to flow or not. 

Short Circuits

DO NOT DO THIS, but if you connect a wire directly from the positive to the negative side of a power supply, you'll create what is called a short circuit. This is a very bad idea. Without a load, there is nothing to slow or resist current flow. 

You can also cause an issue if you have loads on your circuit but they do not resist enough current. This will also cause excess heat like in a short circuit and overload the circuit. This isn't quite a short circuit, but it's close. This most often happens when you use the incorrect resistor value, which lets too much current flow through to another component such as an LED.

Experiment with Circuits! Wire Game

The wire game is a simple carnival type game that has you guiding a metal wand with a hook down a wire with different shapes and bends. The goal is to make it from one end to the other without touching the wand to the wire path which will cause the buzzer to go off. Using our knowledge of simple circuits we are going to make a circuit with a battery, conductors, and a load. In this project the load is a buzzer. Instead of a switch we can open and close our circuit be connecting and disconnecting our conductors.

Step One

Cut a piece of foam core or card board to approximately nine by four inches. Poke a hole through about half way between and one inch from year side. 

Step Two

Grab about two feet of 14 gauge solid core wire. Cut it in two pieces- one about 18" and the other 6". Bend the 18" wire into a gentle bend of any shape you want-- this will be your path. Bend a small hook into the 6" wire. 

Step Three

Add a piezo buzzer and battery to the base and secure with tape or glue. Add a 9V Battery connector to the battery- attach one end to the wire path and the other to a foot of flexible stranded wire. Attach the other end of the one foot flexible wire to the wand. You can do this by wrapping the wires around each other and securing with electrical tape.