AC/DC ELECTRICAL CIRCUIT
This worksheet needs to be completed and brought to class for Tue LAB.
Skill 1
Complete step 1, Steps 2-5 will be completed in the LAB.
Skill 2
Complete steps 1-9
Activity 1 will be completed in the LAB.
Skill 3
Complete steps 1-7
Skill 4
Complete step 1-2, Steps 3-10 will be completed in the LAB.
Skill 5
Complete step 1-2, Steps 3-6 will be completed in the LAB.
Skill 6
Complete step 1-6.
Skill 7 – Skill 10
Will be completed in the LAB.
SKILL 1 CALCULAT E SERIES RESIS TANCE GIVEN EACH LOAD’S
RESISTANC
E
Procedure Overview
In this procedure, you will calculate total resistance in a series circuit and
verify your calculations by measuring the total
resistance
.
□ 1. Calculate the total resistance of the circuit in figure 1-1.
RT= _____________________ _
+
12
V
R1=10n R2 = 25n
Figure 1-1. Calculation of Total Resistance
Show all your work to calculate Total Resistance
RT =
LB227-BD03UEN-E1 -S01, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
R3 = 25n
(Ohms)
S01-1
SKILL 1 CALCULATE SERIES RESISTANCE GIVEN EACH LOAD’S RESISTANCE
□ 2. Connect the series circuit shown in figure 1-2.
This will allow you to prove that the resistances add together in series.
NOTE
You will not need to connect the power supply to take the measurements
in this circuit.
R1 = 10Q R2 = 25Q R3 = 25Q
POINT A POINT B
Figure 1-2. Series Circuit
□ 3. Measure the resistance of each load.
Resistance RI = __________________ _
Resistance R2 = __________________ _
Resistance R3 = __________________ _
(Ohms)
(Ohms)
(Ohms)
□ 4. Measure the total resistance by placing one lead at point A and the other lead
at point B.
Total resistance=
___________________ (Ohms)
There might be a slight variance.
□ 5. Disconnect the circuit and store all components.
LB227-BD03UEN-E1 -S01, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
S01-2
mclass
Typewritten Text
This step will be completed in the LAB.
SKILL 2 USE OHM’S LAW TO CALCULATE VOLTAGE, CURRENT
,
AND RESISTANCE IN A SERIES CIRCUIT
Procedure Overview
In this procedure, you will calculate voltage, current, and resistance in a
series circuit by applying Ohm’s Law.
□ l. Calculate the power supply’s voltage for the circuit shown in figure 2-1 if the
current is 2 amps and resistor Rl has a resistance of 20 ohms.
R
1
= 20 Q
Figure 2-1. Voltage Calculation
Voltage (E) = ___________________ (Volts)
The solution to this problem is found by using Ohm’s law
E
LB227-BD03UEN-E1 -S02, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
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SKILL 2 USE OHM’S LAW TO CALCULAT E VOLTAGE, CURRENT, AND RESISTANCE IN A SERIES CIRCUIT
□ 4. Calculate the current in the circuit shown in figure 2-3. The power supply is
a constant voltage power supply.
Current (I)= __________________ (Amps)
24 V
+
100
Figure 2-3. Current Calculation
Being able to calculate current in a circuit is important if you want to add a
circuit protection device. You must know the total current in order to select
the properly-rated protection device. If the current is much above the device’s
rating, the device will blow or trip when operated in the circuit, as you will
see later in this LAP.
□ 5. Calculate the current in the circuit shown in figure 2-4 using the voltage and
resistance values.
Current=
24V
+
30 90
Figure 2-4. Current Calculation
LB227-BD03UEN-E1 -S02, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
(Amps)
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SKILL 2 USE OHM’S LAW TO CALCULATE VOLTAGE, CURRENT, AND RESISTANCE IN A SERIES CIRCUIT
□ 6. Calculate the resistance of the load in figure 2-5 if the voltage applied to the
circuit is 120V and the current is 3A.
R= _______________________ _ (Ohms)
1
20V
I= 3A
R
Figure 2-5. Resistance Calculation
Knowing the resistance of a load is important in designing a circuit because
of the effect it has on the current and voltage. Sometimes loads do not specify
their resistance. However, Ohm’s Law gives us a means of determining an
unknown resistance value.
□ 7. Calculate the resistance of the load shown in figure 2-6. The voltage and
current are shown.
Resistance= _____________________ (Ohms)
+
r;1.2A
Figure 2-6. Resistance Calculation
LB227-BD03UEN-E1 -S02, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
12V
R
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SKILL 2 USE OHM’S LAW TO CALCULATE VOLTAGE, CURRENT, AND RESISTANCE IN A SERIES CIRCUIT
□ 8. Calculate the current in the circuit shown in figure 2-7.
Current= _____________________ _ (Amps)
35V
12n
5£2 20£2 7£2
Figure 2-7. Current Calculation
□ 9. Calculate the unknown resistance value in the circuit shown in figure 2-8.
HINT
You will need to determine the voltage drop across both resistors.
Resistance= ____________________ _
I= .8A
R
Figure 2-8. Resistance Calculation
LB227-BD03UEN-E1 -S02, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
24V
70
(Ohms)
S02-5
SKILL 3 CALCULATE THE TOTAL POWER USED BY A SERIES CIRCUIT
Procedure Overview
In this procedure, you will calculate the total power used in a series circuit.
This is a common calculation designed to determine the sizes of components
needed in the circuit.
□ 1. Calculate the total power used in the circuit shown in figure 3-1.
PT= ______________________ (Watts)
The solution is found as follows:
Since we know the total voltage and current, we can use the first power in
series formula.
PT = IT X ET
+
11 = .19A 24V
Figure 3-1. Total Power Calculation
R, = 4
20
LB227-BD03UEN-E1 -S03, REV B CIRCUIT ANALYSIS
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SKILL 3 CALCULATE THE TOTAL POWER USED BY A SERIES CIRCUIT
□ 2. Calculate the power used by the circuit shown in figure 3-2.
p = ______________________
(Watts)
Since the current and resistance are given, we can use what formula
P=_____
p =
I =2A
Figure 3-2. Total Power Calculation
V
+
□ 3. Calculate the power used by the circuit shown in figure 3-3.
P = ____________________ (Watts)
I =2A
Figure 3-3. Total Power Calculation
LB227-BD03UEN-E1 -S03, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
24V
+
R
S03-2
SKILL 3 CALCULATE THE TOTAL POWER USED BY A SERIES CIRCUIT
□ 4. Calculate the power used by the circuit shown in figure 3-4.
PT= ______________________ (Watts)
1=3A
20
Figure 3-4. Total Power Calculation
100
□ 5. Calculate the power used by the circuit shown in figure 3-5 using the total
resistance.
PT= _______________________ (Watts)
+
I= 2A
R, =2Q
Figure 3-5. Total Power Calculation
LB227-BD03UEN-E1 -S03, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
R
2
= 4 0
S03-3
SKILL 3 CALCULATE THE TOTAL POWER USE D BY A SERIES CIRCUIT
□ 6. Perform the following substeps to calculate the total power used in the
circuit shown in figure 3-5 by calculating the individual power used by each
component.
Figure 3-5 shows a circuit with the current and each resistance given. The
source voltage is not known.
A. Calculate the power dissipation of RI.
PR 1 = _____________________ (Watts)
B. Repeat substep A for R
2
.
PR2 = ______________________ (Watts)
C. Calculate the total power dissipation by adding the individual power
dissipations.
PT = ______________________ (Watts)
The total power used is ___ watts. This should be the same as you
calculated in step 5.
□ 7. Calculate the total power used by the circuit shown in figure 3-6.
PT= ______________________ (Watts)
J 1 = 1.5A
R, = 47Q
Figure 3-6. Total Power Calculation
LB227-BD03UEN-E1 -S03, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
S03-4
SKILL 4 CALCULATE THE MAIN LINE CURRENT IN
A PARALLEL CIRCUIT
Procedure Overview
In this procedure , you will calculate the total current in a parallel circuit
using Kirchhoff’s current law. You will then connect a circuit and measure the
current in each branch to verify your calculations .
□ 1. Use Ohm’s Law to calculate the current in each branch of the circuit in figure
4-1.
Current 1
1
= ____________________ (Amps)
Current 1
2
= ____________________ (Amps)
Current 1
3
= ___________________ (Amps)
+
12V
Figure 4-1. Main Line Current Calculation
□ 2. Calculate the main line current using the branch currents you calculated in
step l and Kirchhoff’s Current Law.
lr = 1
1
+1
2
+1
3
Main line current= _________________ (Amps)
LB227-BD03UEN-E1 -S04, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
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– – – — — – — ————–
SKILL 5 CALCULATE THE TOTAL PARALLEL RESISTANCE
Procedure Overview
In this procedure, you will calculate the total resistance of the circuit using
the parallel resistance formula. In the first step you will be given an example.
□ 1. Calculate the total resistance of the circuit in figure 5-1.
� = ___________________ (Ohms)
1
R =—-r
1 1 1
-+-+
R
,
R R
,
�=0.24A
+
12V R= 1
150D
Figure 5-1. Total Resistance Calculation
R=
2
300D
R=
3
100n
LB227-BD03UEN-E1 -S05, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
S05-1
SKILL 5 CALCULAT E THE TOTAL PARALLEL RESISTANCE
NOTE
Each time another load is added to a parallel circuit, the effective resistance
is lowered. This is exactly the opposite effect of adding a load to a series circuit,
which would increase the effective resistance of that circuit.
This is the reason the main line current increases as more branches are
added. Since the total resistance is reduced, Ohm’s Law says that the current
must increase since the voltage is constant.
□ 2. Calculate the total resistance of the parallel circuit shown in figure 5-2.
(Ohms)
+
12V
Figure 5-2. Total Resistance Calculation
LB227-BD03UEN-E1 -SOS, REV. B CIRCUI T ANALYSIS
Copyright© 2018 Amatrol, Inc.
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SKILL 5 CALCULATE THE TOTAL PARALLEL RESISTANCE
□ 3. Now connect the circuit shown in figure 5-2.
Do not connect the circuit to the power supply.
Any time you make resistance measurements m a circuit, you should
disconnect the circuit from the power supply.
□ 4. Measure the resistance of each branch of the circuit with the DMM.
Remember to disconnect one side of the load in that branch from the circuit
before measuring. Reconnect each load after you make your measurement.
R =
I
R =
2
___________________ (Ohms)
___________________ (Ohms)
R1 = ——————- (Ohms)
□ 5. Measure the total resistance of the circuit, as shown in figure 5-3.
Total resistance= ___________________ (Ohms)
DISCONNECTED
SUPPLY Q
Figure 5-3. Total Resistance Measurement
□ 6. Disconnect the circuit and store all components.
LB227-BD03UEN-E1 -S05, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
S05-3
SKILL 6 CALCULATE THE TOTAL POWER USED
IN A PARALLEL CIRCUIT
Procedure Overview
In this procedure, you will calculate the total power used in a circuit. This
calculation uses the same principles used to calculate the power in a series
circuit except that the calculation of total resistance is different.
In steps I and 2 you will be given some examples. Then you will do it
yourself.
□ 1. Calculate the total power used in the circuit shown in figure 6- 1.
The power in a parallel circuit can be calculated using any of the three
methods used for series circuits:
• Method A – Calculate total resistance of the parallel circuit and use the FR
formula.
• Method B – Determine the total voltage and current and use the I x E
formula
• Method C – Calculate the power consumed by each component and add
them together, as follows:
p T = pl + p2 + p3 + ‘ ‘ .
I= 3AMPS
+
E =24V R = 1
Figure 6-1. Total Power Used by a Parallel Circuit
R =
2 R = 3
PT= ______________________ (Watts)
Since the circuit in figure 33 shows the total voltage and current, method B (I
x E) can be used as follows:
Pr = IrxEr
Pr =
LB227-BD03UEN-E1 -S06, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
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SKILL 6 CALCULATE THE TOTAL POWER USED IN A PARALLEL CIRCUIT
□ 2. Perform the following substeps to calculate the total power used in the circuit
shown in figure 6-2.
I= 2A
+
Figure 6-2. Total Power Calculation
R
1
= 10D
A. Calculate the total resistance, �-
1
R =–
T 1 1
-+
R R
1 2
�= _____________________ Ohms
B. Calculate the total power.
P
T
= I2 X Rr
P = ______________________ (Watts)
T
LB227-BD03UEN-E1 -S06, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
806-2
SKILL 6 CALCULATE THE TOTAL POWER USED IN A PARALLEL CIRCUIT
□ 3. Perform the following substeps to calculate the total power used in the circuit
shown in figure 6-3. Use method C to solve it.
+
20V
MAXIMUM
POWER
=80W
R =
1
500
Figure 6-3. Total Power Calculation
R =
2
20 n
A.
R =
3
1 on
,
Calculate the current in each branch of the circuit.
IR 1 = ______________________ (Amps)
IR2 = ______________________ (Amps)
I = _____________________ (Amps)
R
B. Now calculate the power dissipation of each load using the basic power
formula (P = Ix E).
p =
I
p =
2
p =
3
(Watts)
(Watts)
(Watts)
Since this is a parallel circuit, the voltage across each branch is equal to
the source voltage.
C. Calculate the total power used by the circuit.
PT = ———————-�
LB227-BD03UEN-E1 -S06, REV B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
(Watts)
S06-3
SKILL 6 CALCULATE THE TOTAL P OWER USED IN A PARALLEL CIRCUIT
□ 4. Calculate the power used by the circuit shown in figure 6-4.
+
V= 24V
Figure 6-4. Total Power Calculation
10W 25W
PT= ______________________ (Watts)
□ 5. Calculate the power used by the circuit shown in figure 6-5.
I =2A
+
Figure 6-5. Total Power Calculation
100
300
150
PT= ______________________ (Watts)
o 6. Solve the following design problem.
Determine how many 1 00W light bulbs can be connected to a common
commercial building’s circuit if the source voltage is l 20 VAC and the
maximum current that can be provided is 20A.
HINT: What is the maximum output power that the source can provide with
the 20A limit?
LB227-BD03UEN-E1 -S06, REV. B CIRCUIT ANALYSIS
Copyright© 2018 Amatrol, Inc.
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- SCN_0002
- SCN_0003