Series If you add a resistor (like another light): Total resistance goes UP since all the current has must go through each resistor.
Adding Resistors to Series: Current in the circuit will go DOWN (lights will dim) If you remove a light bulb or one burns out—all go out!
Current in Series Current is the same at all points Use Ohm’s Law to find current using resistance and voltage
Calculating Current Example: A 6 V battery is connected to
Voltage in Series Voltage is reduced by each resistance – voltage drop
Calculating Voltage Example A 6 V battery is connected to a series circuit. If the current is 2 A, what is the voltage across a 2Ω resistor?
Resistance in Series Add up all resistors to get total Total resistance will go up because all of the current must go through each resistor.
Adding resistances in series Each resistance in a series circuit adds to the total (or equivalent) resistance of the circuit. R total = R 1 + R 2 + R 3... Total resistance (ohms) Individual resistances
Calculating Resistance Example: A series circuit contains a 12Ω, 10 Ω and 8Ω resistor. What is the equivalent resistance?
20.1 Voltage in a series circuit Each separate resistance creates a voltage drop as the current passes through. As current flows along a series circuit, each type of resistor transforms some of the electrical energy into another form of energy Ohm’s law is used to calculate the voltage drop across each resistor.
Sample Problem #1 Draw a series circuit with two 1.5 V batteries, 3 resistors, and a current of 0.5 A. 1. What is the total voltage of the circuit? 2. What is the resistance of each resistor? 3. What is the voltage drop across each resistor? Label on your circuit.
Do Now (10/24/13): Draw an example of what you a parallel circuit would look like.
Extra Credit Opportunity Open House – Sunday, October 28, 12 – 3 PM 5 service learning hours! Free pizza!! Extra credit!!!
Parallel Circuits Has at least one point where current divides More than one path for current to flow Paths are also known as branches
Practice problem #2 Draw a parallel circuit with two resistors (one on each branch) and a 12 V battery. 1. What is the voltage through each resistor? 2. What is the current flowing through each branch?