# Voltage Def the energy or pushing force available

Voltage • Def : the energy or pushing force available to move electrons through a circuit • Unit: volt (V) • Symbol: V • Measured using an instrument called a voltmeter V

If = 1. 5 volts 3. 0 V ? V

Potential Difference Def: difference between the charges at the beginning of a circuit and at the end Charges flow because of ‘potential difference’.

3. 0 V 0. 0 V • By the time a charge travels through a circuit it will essentially have lost its voltage or “push”

Resistance • Def: how much the voltage decreases as it passes through each resistor on the way back to the negative end of the battery • The more light bulbs you have in a series circuit, circuit the dimmer they are because they have to share voltage

• Resistance is the tendency for materials to oppose the flow of electricity §Symbol: (R) Unit: ohm (Ω) Measured by an ohmmeter Ω §High resistance = insulators. §Low resistance = conductors. §Anything using electricity is a resistor!!

Your Turn… • Find the voltage drop across the missing bulbs 40 5

• In a parallel circuit, circuit the voltage drop across EACH resistor is equal to the total voltage • Light bulbs wired in parallel have the same brightness!

Current • Def : the rate of “FLOW” FLOW of electrons through a wire • Unit: Amperes (amp) • Symbol: I • It is measured using an ammeter A

• Current in a series circuit is the same for each resistor (light bulb).

Current is divided up between each path; Each path gets the necessary number of amps.

TYPES of CURRENT Direct Current (DC) Alternating Current (AC) flows in one direction reverses back and forth Ex. - Batteries Ex. – Household current

to Electrical Current Which of the following do you think would be most resistant to electrical Plastic current? OR Insulator Conductor

Resistance is affected by… • Length • The longer the wire, the greater the resistance • Diameter • The smaller the diameter, greater the resistance • Material • Poor conductors have high resistance • Temperature • The hotter the wire, the greater the resistance

Match the word on the left to the phrase on the right. Resistance How Fast? Current How much? Ohms or R AMPS (I) Voltage Volts (V) How much is it slowed down?

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