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ELIZABETHTOWN COMMUNITY AND TECHNICAL COLLEGE
BEX 100 BASIC ELECTRICITY FOR NON MAJORS
LECTURE GUIDE – UNIT 6
Instructor: Jerry Brown
Reference: Delmar’s Standard Textbook of Electricity, Third Edition
SERIES CIRCUITS
Objectives
At the completion of the lesson, the student should be able to:
1. Discuss the properties of series circuits
2. List three rules for solving electrical values of series circuits
3. Compute values of voltage, current, resistance and power for
circuits
series
INTRODUCTION
There are three basic types of electrical circuits:
Series
Parallel
Combination (Series/Parallel)
Series Circuits
A series circuit only has one path for current to flow
Voltage Drops in a Series Circuit
Voltage Drop – the amount of voltage needed to push the current
through the resistor
Rule #1 – The sum of all the voltage drops across the resistors must equal
the applied voltage.
Current Values in a Series Circuit
Rule #2 – The current in a series circuit is the same at any point in a
circuit.
Resistance Values in a Series Circuit
Rule #3 – The total resistance in a series circuit is the sum of the
individual resistors.
Solving Series Circuits
First Step – Find the total resistance in the circuit, then use Ohm’s Law
to solve for total current and total power.
Step 2 – Once the total current is found, then the individual current
passing through each resistor is known.
Step 3 – Use Ohm’s Law to solve for the remaining unknowns
Rule #2 – The current in a series circuit is the same at any point in a
circuit.
Rule #2 – The current in a series circuit is the same at any point in a
circuit.
Voltage Dividers – (Use Ohm’s Law for each resistor in the circuit)
Voltage is divided based on the principle that the sum of the voltage
drops across each resistor will equal the supply voltage, and
The Current through the circuit will be the same at any point in the
circuit
Voltage Polarity
Determined by observing direction of current flow
Current flows from negative to positive
Ground Symbol in Schematics
Earth Ground Symbol
An earth ground is made by physically driving a rod or pipe into the
ground
Chassis Ground Symbol
A ground point used as a common connection for various circuits
A common practice in schematics is to use the earth ground symbol to
indicate a chassis ground
REVIEW
1. Series circuits have only one path for current flow
2. The individual voltage drops in a series circuit can be added to equal the
applied voltage
3. The current is the same at any point in a series circuit
2
4. The individual resistors can be added to equal the total resistance of the
circuit
5. Fuses and circuit breakers are connected in series with the devices they
are intended to protect
6. The total power in any circuit is equal to the sum of the power dissipated
by all parts of the circuit
7. When the source voltage and total resistance are known, the voltage drop
across each element can be computed using Ohm’s Law
REVIEW QUESTIONS
1. Define a series circuit
2. State the three rules for solving series circuits:
a.
b.
c.
3. A series circuit has individual resistor values of 200 Ω, 86 Ω, 90 Ω, 180
Ω, and 150 Ω. What is the total resistance of the circuit?
4. A series circuit contains five resistors. The total voltage applied to the
circuit is 120 V. Four resistors have voltage drops of 35 V, 28 V, 22 V,
and 15 V. What the voltage drop of the fifth resistor?
5. A circuit has three resistors connected in series. Resistor R2 has a value
of 220 Ω and a voltage drop of 44 V. What is the total current flow in
the circuit?
6. A series circuit has resistance values of 160 Ω, 100 Ω, 82 Ω, and 120 Ω.
Complete the following values:
ET =
V
RT =
Ω
IT =
A
PT =
E1 =
V
R1 =
Ω
I1 =
A
P1 =
E2 =
V
R2 =
Ω
I2 =
A
P2 =
E3 =
V
R3 =
Ω
I3 =
A
P3 =
E4 =
V
R4 =
Ω
I4 =
A
P4 =
3