Light a bulb You are given: Wires, a bulb and a battery. Your job is to: Light the bulb.
To light a bulb, the most important thing is: There must be a complete path, or NO GAPS. This is a CIRCUIT.
Electric Circuit An electric Circuit is any path along which electrons can flow. For a continuous flow of electrons, there must be no gap in the circuit. An electric switch must be closed for electricity to flow. There are two types of electric circuits: Series Circuits Parallel Circuits
Series Circuits There is only a single path for electrons to flow. Disadvantage: If one bulb fuses, the current in the circuit stops.
In a series circuit The current through each bulb is the same. The total resistance is the addition of all resistances. The current in the circuit is equal to the battery voltage divided by total resistance.
Series Circuit The total resistance in a series circuit is the SUM of all resistances. Ex: The Total Resistance of two 8 Ω resistors connected in series is ____. = What is the total resistance of three 4 Ω resistors in series? 4+4+4 = 12 Ω
Parallel Circuits Each bulb is connected to the battery terminals. Each bulb operates INDEPENDENT of each other. If one bulb fuses, it does not disrupt other bulbs.
In a parallel circuit The voltage across each bulb is the same. The total current in the circuit equals the sum of currents in all the branches.
Parallel Circuit The Total resistance for a pair of equal resistors in parallel is HALF the value of either resistor. Ex: The Total Resistance of two 8 Ω resistors connected in parallel is ___. = Ex: The Total Resistance of two 10 Ω resistors connected in parallel is ___.
Can I have three volunteers please? How can they arrange themselves to form a series circuit? How much current will flow through each? How much voltage will be across each? How can they arrange themselves to form a parallel circuit? How much current will flow through each? How much voltage will be across each?
Differentiate between Series Circuit Only 1 path for current If one bulb fuses, current stops. Resistance of a series circuit is more Current in a series circuit is less Voltage is divided among all bulbs Parallel circuit Multiple paths for current If one bulb fuses, others still work Resistance of a parallel circuit is less Current in a parallel circuit is more. Voltage across all bulbs is the same
For now Open to Pg 714 and answer Q 2, 3, 5, 6, 7, 8, 9 Next class, test on Electricity Next week – Physics Finals