C ELLS IN S ERIES AND P ARALLEL Science 9 W HAT IS A CIRCUIT ? A circuit is when electrical current flows through a controlled path. A FEW DEFINITIONS . Electric Current the movement or flow of electric charges from one place to another. Electric Circuit a controlled path in which electric current passes through. Electric circuits are used to convert electrical energy into other forms of energy that we need such as heat or light. These circuits convert electrical energy into other forms C IRCUIT B ASICS Power / Energy Source: This supplies the circuit with energy Important to Know! Electricity travels from the negative end to a positive end of a battery Wires: This allows the current electricity to flow Load or Output device: this converts the electrical energy to other forms such as heat or light. It often also acts as a resistor (something that slows but does not prevent the flow of electricity) Switch: opens and closes the circuit Draw a basic circuit and label its parts. 3. Electric Circuit Control Device a switch that controls the electricity (turn on and off). 4. Connectors the conducting wires that provide the controlled path for electric current to flow to each part of the circuit. 1. Source of electrical Energy the place or thing that generates the electrical energy. 2. Electrical Load anything that converts electrical energy into the form of energy needed Closed Circuit a circuit that is closed or on or allowing electricity to flow through. (the computer will work) Open Circuit a circuit that is open or off or not allowing electricity to flow through. (the computer will not work) T HERE ARE TWO MAIN TYPES OF CIRCUITS : Series Parallel You can put the load (light) or the power source (battery) in series or parallel S ERIES AND P ARALLEL C IRCUITS There are advantages for putting the energy source in series or parallel. A DVANTAGE OF A S ERIES C IRCUIT : Increased the electric potential (voltage) produced at the output terminals of the batteries (a brighter light!) As the electron travels through the consecutive batteries, it gets an additional boost of energy increasing its voltage. A DVANTAGE OF P ARALLEL C IRCUITS With two cells there is twice as much electric energy available; therefore the load can operate twice as long before running out of energy. C ELLS IN S ERIES AND P ARALLEL S ERIES C IRCUITS Series: circuit is wired in one single path. Ex: Christmas lights, if one bulb burns out, all the lights have to be checked to find the burned out bulb. P ARALLEL C IRCUITS Parallel: Circuit passes through separate circuits called branch circuits. Because each bulb is connected to its own branch circuit, it does not affect the other bulbs. Q UESTIONS : Make a chart listing the different parts of an electric circuit. State a function for each part and provide two examples. In which way does the electric charge flow around the circuit? List four examples of electrical loads in the kitchen that convert electrical energy to: Light energy Mechanical energy Repeat this for electrical devices in the basement/laundry room, then for devices in a car. Y OUR H OUSE AS A C IRCUIT Think about how your house is wired. Where does the energy come from? Draw your house as a circuit. Include all of the sources of energy, electrical loads, wires, and switches. Include as much detail as possible (at least 3-4 items per room)