Current and Voltage Light Bulb successful scenarios Current

Current and Voltage

Light Bulb successful scenarios

Current �

Voltage �Voltage also known as “Potential difference” is what causes charge to be “pushed” and “pulled” around a circuit of conductors �Represented in equation with ◦ ΔV �Units for Voltage? ◦ Volt �Sources of potential difference? ◦ Uneven charge distribution �Generators �Solar Panels �Batteries

Resistance �A measurement that prevents or hinders the flow of charge/current. �Unit for Resistance? ◦ Ohms (Ω)

Resistance Analogy �Traffic analogy ◦ A traffic jam causes the number of cars passing through a certain point to decrease ◦ A resistor causes the number of charge carriers passing through a certain point to decrease ◦ Flow rate is represented in circuits by current

Electrical Diagrams (Circuits) Ammeter: A device to measure the flow rate (current) through a conductor A Battery: A device that causes the potential difference in the circuit. Resistor V Voltmeter: A device to measure the uneven distribution of charge (Voltage) across a conductor

Series and Parallel Circuits

Ohm’s Law. Results �Purpose: ◦ To find the relationship between potential difference (IV) and current (DV) �Relationship between voltage and current? ◦ Directly proportional ◦ Resistance measured in ohm’s (Ω)

Ohm’s Law Continued ◦ Product of current and voltage �If current is increased through a lightbulb what will happen to it’s brightness? �It will get brighter �If voltage is increased across a lightbulb what will happen to it’s brightness? �It will get brighter ◦ Units watt ◦ Area represents power dissipated by the resistor �P=IV �Substituting in the variables from V=IR

Ohm’s Law Example Question �A Voltage of 6. 0 V is connected to a purely resistive lamp and a current of 2. 0 amperes flows. All the wires are resistance-free. What is the resistance of the lamp? Then, find the amount of power produced from the lamp

Series Circuits What measurements could be made to study how the combination of resistors might affect the current and potential difference at different parts of the circuit? � A V

Series Circuits �In series circuits: ◦ Current is the same in each segment of the circuit ◦ Voltage across battery equals sum of voltages across circuit components ◦ Ratio of voltage across resistors equals ratio of resistance ◦ Using Ohm’s Law relationship between voltage, current, and resistance

Series Example Problem R 1=8Ω R 2=12Ω Rs =R 1+R 2 Rs =8 Ω +12 Ω Rs=20 Ω

Series: Try it yourself R 1=20Ω Rs =R 1+R 2+R 3 R 2=30Ω Rs = 20Ω+30Ω+50Ω R 3=50Ω Rs = 100 Ω Rs =R 1+R 2+R 3

Parallel Circuits What measurements could be made to study how the combination of resistors might affect the current and potential difference at different parts of the circuit? � A V

Parallel Circuits Continued �In parallel circuits: ◦ Voltage is the same in each segment of the circuit ◦ Current through battery equals sum of currents through each branch ◦ Ratio of current through resistors equals inverse ratio of resistance ◦ Using Ohm’s Law relationship between voltage, current, and resistance

Parallel Example Problem � �

Parallel: Try it yourself