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A GENDA – M AY 7 Talk about review Finish Ch 22 notes Ch 23 notes Virtual lab Monday: Ch 22 and 23 bkwk due and virtual lab due. Take test if not here Wednesday. C H . 23 E LECTRIC C IRCUITS Create a circuit with 1 battery and 1 light Create a circuit with 2 batteries and 1 light Create a circuit with 2 batteries and 2 lights connected in series Create a circuit with 2 batteries and two lights in parallel Create a circuit with 2 batteries and 1 light parallel with 2 in series S ERIES C IRCUITS A series circuit is a circuit in which all of the current travels through each device S ERIES C IRCUITS Voltage drops / potential difference The potential difference of the generator is equal to the potential difference across each resistor (lamp) Vsource VA VB S ERIES C IRCUITS Resistance in the circuit is equal to sum of the resistances in each component R RA RB ... S ERIES C IRCUITS Current in the circuit is equal to the potential difference in the whole circuit divided by the resistance of all of the components Vsource I R E XAMPLE Three 20Ω resistors are connected in series across a 120 V generator. What is the equivalent resistance of the circuit? What is the current in the circuit? PARALLEL C IRCUITS A circuit with several current paths PARALLEL C IRCUITS The voltage through each path is the same The current can be found through each individual path The total current is that of all of the paths combined A 120 V 24Ω 6Ω 120 V 120 V 9Ω 120 V PARALLEL C IRCUITS The resistance for the whole parallel circuit will be less than each resistor because each resistor offers an additional path for the current Equation for finding the total resistance of a parallel circuit 1 1 1 ... R RA RB E XAMPLE A 120Ω resistor, a 60Ω resistor, and a 40Ω resistor are connected in parallel and placed across a 12 V battery. What is the equivalent resistance of the parallel circuit? What is the current through the entire circuit? What is the current through each branch? 23.2 S AFETY D EVICES Fuse – A short piece of metal that melts when the current traveling through it is too large Short Circuit – When there is very low resistance in a circuit. This can easily cause fires if there is no fuse or circuit breaker to stop the high levels of current E XAMPLE Two 60Ω resistors are connected in parallel. This parallel arrangement is connected in series with a 30Ω resistor. The combination is then placed across a 120V battery. Draw a diagram of the circuit. What is the equivalent resistance of the parallel portion? What single resistance could replace the three original resistors? What is the current in the circuit? What is the voltage drop across the 30Ω resistor? What is the voltage drop across the parallel portion of the circuit? What is the current in each branch of the parallel portion of the circuit? B KWK P550: 1, 4, 7, 8, 15, 21, 24, 28, 32