Diagramming circuits

Ohm’s Law Mnemonic Definitions Current: the number of electrons that go through a wire in one second Voltage: the pressure that pushes the electrons Resistance: the material property that makes it hard to push an electron through a wire Power: the rate at which energy is used up. The more power, the brighter a light bulb. V = IR R = V/I I = V/R

Ohm’s Law Mnemonic P = IV where P = Power (in Watts, the rate at which energy is consumed) I = Current V = Voltage Typical household voltage is 120V.

Important equations for Electricity V T = V 1 = V 2 = V 3 = … 1/R T = 1/R 1 + 1/R 2 + 1/R 3, … I T = I 1 + I 2 + I 3 + … Parallel Circuits V T = V 1 + V 2 + V 3 + … R T = R 1 + R 2 + R 3 + … I T = I 1 = I 2 = I 3 = … Series Circuits V = Voltage (Volts) I = Current (Amps) R = Resistance (Ohms) In a series electric circuit all of the electrons must flow through the same elements. In a series circuit each resistor adds to the total resistance. In a parallel electric circuit electrons may flow through different circuit elements. In a parallel circuit each resistor provides another way for electrons to flow.

A + VV V 7 =3 V 6 = 5 I 4 = R 7 = A I 5 = VV V 8 = R 8 = 2 I T = I 1 = I 2 = I 3 = … V T = V 1 + V 2 + V 3 + … R T = R 1 + R 2 + R 3 + … Series Circuit

A ITIT R1R1 V T + R2R2 V 2, I 2 V 1, I 1 VV I T = I 1 = I 2 = 0.4A V T = V 1 =R 1 = 100 Ohms R T = R 2 = 200 Ohms V 2 = Parallel Circuit

A ITIT R1R1 VTVT R2R2 V 2, I 2 V 1, I 1 VV I T = I 1 = I 2 = 1A V T = V 1 =R 1 = 200 Ohms R T = R 2 = 200 Ohms V 2 = Parallel Circuit