5.8 Circuits:  A circuit is made up of a power supply, connecting wires & various components that allow current to leave a power source, travel through the components & return back to the power source.

Common Electric Symbols Battery/Power Source Bulb

Common symbols (cont’d) Switch Push-button Switch Resistor Voltmeter Ammeter VA

What are we doing?  Send 1 person to pick up: 1 battery & 1 light bulb & holder 2 wires  Make the light bulb light up!  Once you do … go get a switch and add it to your circuit.  Draw a circuit diagram. HAND IT IN.  Return the materials.

Circuits Power Supply Resistor A Ammeter v Voltmeter Switch Light bulb

Types of Circuits:  There are 2 types of circuits:  1.Series Circuit  2.Parallel Circuit SERIES Trick to help identify type of circuit: Series:Pen follows wire Parallel: Pen can go in more than one direction PARALLEL

Series Circuits:  Components are connected end to end  Current only follows one path  If one part of the circuit is broken, the entire circuit will stop functioning  Eg: Some Christmas tree lights

Parallel Circuits:  Current can follow at least 2 different paths  If part of the circuit is defective another part may still be able to operate.  Eg: headlights on a car

Series or Parallel? A A SERIES PARALLEL

AST stop here!  In a series circuit, the Amps remain constant throughout the whole circuit Amps = 2A

Volts, Ohm’s and Amps in a Series Circuit  In a series circuit, the Amps remain constant throughout the whole circuit Amps = 2A

 However, in a series circuit at each resistor the volts change. When you add up all the voltage at each resistor, you end up getting the total volts going through the circuit. Amps = 2A Volts 2 = 3V Volts 3 = 2V Volts 1 = 2V Volts total = 7V V T = V 1 + V 2 + V 3 + …

 In a parallel series, each line of wire has a different amount of amps. When added the amps together, you get the total amount of amps in the entire circuit. Amps 3 = 1A Amps 2 =.5A Amps 1 =.5A

 However, in a parallel circuit if you have a total of 3 volts in the circuit, each resistor will only have 3 volts Amps 3 = 1A Amps 2 =.5A Amps 1 =.5A Volts Total = 3V Volts 1 = 3V Volts 2 = 3V Volts 3 = 3V

For circuits in:  Series: Amps stay the same everywhere in the circuit. Volts are split over each resistor but add up to V total.  Parallel: Amps split at each resistor but add up to A total. Volts stay the same everywhere in the circuit. 5.9 Kirchhoff’s Laws about Volts, Ohms & Amps.