Unit 4- Building from Schematics--Continued EET 110 Electronics Survey I

Topics to Cover Ohm’s Law as applied to Parallel Circuits Ohm’s Law as applied to Parallel Circuits Review Types of representations Review Types of representations Wiring from schematics Wiring from schematics

Ohm’s Law Relationships Voltage (E) Amperes (I) Resistance (R) E= I X R I= E/R R= E/I E IR

Relationships in Parallel Circuits Parallel Circuit has multiple paths for electron flow through devices wired in the circuit E T = E 1 =E 2 =E 3 =E N R T = R 1 +R 2 +R 3 +R N I T = I 1 +I 2 +I 3 +I N

Parallel Voltage in a circuit The voltage in a parallel circuit is equal to the source voltage. The voltage in a parallel circuit is equal to the source voltage. E T = E 1 =E 2 =E 3 =E N E T = 12v=12v=12v E T = 12v E 1 = 12v E 2 = 12v E 3 = 12v E T = 12v

Kirchhoff’s Current Law The algebraic sum of all currents entering any point will equal the sum of all currents leaving that point. The algebraic sum of all currents entering any point will equal the sum of all currents leaving that point. I T = I 1 +I 2 +I 3 +I N I 1 = 2A I 2 = 4A I 3 = 3A I T = 9A

Parallel Resistance in a Circuit When resistors are connected in a parallel circuit, the total resistance of the parallel circuit is always less than the smallest resistance. When resistors are connected in a parallel circuit, the total resistance of the parallel circuit is always less than the smallest resistance R T = R 1 +R 2 +R 3 +R N R T = 2Ω + 3Ω + 6Ω R T = 1 2Ω + 12Ω + 12Ω 1 12 R T = 12Ω= 1Ω R 1 = 2Ω R 1 = 3Ω R 1 = 6Ω R 1 = 1Ω

Solving for Unknown Values in a Parallel Circuit At each resistor and the total resistors Ohm’s law should hold true. At each resistor and the total resistors Ohm’s law should hold true. The Series Circuit Principles will hold true. The Series Circuit Principles will hold true. E=I x R E T = E 1 =E 2 =E 3 =E N R T = R 1 +R 2 +R 3 +R N I T = I 1 +I 2 +I 3 +I N

Practice Solving the Circuit

Pictorial Drawing of Two Receptacles

Schematic Drawing of 2 receptacles

Schematic Drawing of a switched receptacle

Lab 7 wiring from Schematics 2 switches controlling a light 2 switches controlling a light 3 switches controlling a light 3 switches controlling a light

Representations (cont.) Schematics Schematics –Clearly show Types of devices and conductors Types of devices and conductors Where they should be located Where they should be located Electrical Connections Electrical Connections –Typically for controls or equipment –Provided by engineer, manufacturer

2 switches controlling a light Source Schematic 12 2/g 12 3/g 12 2/g

3 switches controlling a light Source Schematic