Analogy of Electric Circuit to Water Circuit http

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Analogy of Electric Circuit to Water Circuit http: //faraday. physics. utoronto. ca/IYear. Lab/In tros/DCI/Flash/Water.

Analogy of Electric Circuit to Water Circuit http: //faraday. physics. utoronto. ca/IYear. Lab/In tros/DCI/Flash/Water. Analogy. html

measuring current Electric current is measured in amps (A) using an ammeter connected in

measuring current Electric current is measured in amps (A) using an ammeter connected in series in the circuit. A

• Underlying causes of resistance

• Underlying causes of resistance

Series • Current only takes one path. • Current flows through every part of

Series • Current only takes one path. • Current flows through every part of the circuit equally.

Voltage in Series • Voltage is reduced by each resistance – voltage drop

Voltage in Series • Voltage is reduced by each resistance – voltage drop

Adding Resistors to Series: –Current in the circuit will go DOWN (lights will dim)

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!

Resistance in Series • Add up all resistors to get total –Total resistance will

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.

Sample Problem #1 Draw a series circuit with a 3 v potential difference, 3

Sample Problem #1 Draw a series circuit with a 3 v potential difference, 3 identical 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. •

Parallel Circuits • Has at least one point where current divides • More than

Parallel Circuits • Has at least one point where current divides • More than one path for current to flow • Paths are also known as branches

Current in Parallel • Current flows into a branching point, the same total current

Current in Parallel • Current flows into a branching point, the same total current must flow out again • Current depends on resistance in each branch

Voltage in Parallel • Voltage is the same across each branch – because each

Voltage in Parallel • Voltage is the same across each branch – because each branch represents one path back to the source.

Resistance in Parallel • Calculate current in each branch based on resistance in each

Resistance in Parallel • Calculate current in each branch based on resistance in each branch by using Ohm’s Law

Practice problem #2 • Draw a parallel circuit with two resistors (one on each

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?

• The watt (W) is a unit of power. • Power is the

• The watt (W) is a unit of power. • Power is the rate at which energy moves or is used. • Since energy is measured in joules, power is measured in joules per second. • One joule per second is equal to one watt.

Power in electric circuits • One watt is a pretty small amount of power.

Power in electric circuits • One watt is a pretty small amount of power. • In everyday use, larger units are more convenient to use. • A kilowatt (k. W) is equal to 1, 000 watts.