DC Circuits 1 Series Circuits Unit 3
The current is determined by the source voltage and the total resistance. First, calculate the total resistance.
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Voltage
A _____ develops across a resistor in a series circuit because there is a pressure difference due to restriction in flow.
an open
A crack in a circuit board creates _________.
3 times the voltage
A resistor value three times greater than another resistor in a series circuit will have __________.
800 watts
A series circuit with 200 volts applied and 4 amps of current flow consumes how much power?
causes excessive current
A shorted condition ________.
a short
A solder splash creates _________.
200watts
A three-resistor series circuit dissipates the following watts at each resistor; R1=40w R2=60w R3=100w What is the total wattage consumed by the circuit?
is an interruption of current flow
An open condition _____________.
With parallel resistors, it is simple to think in terms of the conductive paths; each resistor adds to the total conductance as given by the following equation: GT=G1+G2+G3+...+Gn Subtstituting1/R for G. 1/RT=1/R1+1/R2+1/R3+...+1/Rn Solve for RT by taking the reiprocal of (that is, by inverting) both sides of the equation. RT= 1/1/R1+1/R2+1/R3+...+1/Rn
Conductance (G) is defined as the reciprocal of resistance,(1/R). It has the unit of siemens (S).
inversely
Current flow is ______ proportional to resistance in a series circuit.
directly
Current flow is _______ proportional to the voltage applied in a series circuit.
True
Current flow is the same value throughout a series circuit. True or False
A series circuit provides only one path for current between two points so that the current is the same through each series resistor. Remember, if there is only one current path between two points, the resistors between thos two points are in series, no matter how they appear in a diagram.
Define series circuit
When a short occurs in a series circuit, there is essentially no voltage across the shorted part. A short has zero or near zero resistance, although shorts with significant resistance values can occur from time to time. These are called resitive shorts. In order to troubleshoot a short, measure the voltafe across each resistor until you get a reading of 0V. This is the straightforward approach and does not use half-splitting. in order to apply the half-splitting method, you must know the correct voltage at each point in the circuit and compare it to measured voltages. see figure 4-61 on page151
Explain the effects on the circuit parameters listed in step 2 when a shorted component develops.
When an open occurs in a series circuit, all of the source voltage appears across the open. The reason for this is that the open condition prevents current through the series circuit. with no current, there can be no voltage drop across any of the other resistors. Since IR=(0A)R=0V, the voltage on each end of a good resistor is the same. Therefore, the voltage applied across a series string also appears across the open component because there are no other voltage drops in the circuit. See figure 4-57 on page 149
Explain the effects on the circuit parameters listed in step 2 when an open develops
RT= 22ohm+22ohm+22ohm+22ohm+22ohm+22ohm+22ohm+22ohm = 176ohms RT=8(22ohm)=176ohms
Find the RT of eight 22 ohm's resistors in series.
If you know the total applied voltage and the total resistance, you can determine the total current by Ohm's law.
IT=Vt/Rt
If you know the voltage drop across one of the series resistor, Rx, you can determine the total current by Ohm's law.
IT=Vx/Rx
41
If the percentage of one resistor is 41 percent of the total resistance, what percent of the applied voltage will be dropped across it?
51 volts
If the resistance of one resistor is 17% of the total resistance, the voltage drop across it is _____ if the power supply is set to 300 volts.
True
In a series circuit, the following formulas will obtain the same value. IT=ET/RT IT=ER1/R1 True or False
The sum of all the voltage drops around a single closed path in a circuit is equal to the total source voltage in that closed path.
Kirchloff's voltage law
aiding
Power supplies with their polarities connected in the ame direction anre referred to as series ________.
refers to a conductor that is the comparison point for voltage measurements in a circuit. It is the conductor that carries the power supply return current. see page 147
Reference ground or common
if one of the batteries in the flashlight is turned around its voltage subtracts because it has a negative value and reduces the total voltage. Vs(tot)= Vs1+Vs2+Vs3= 1.5V-1.5V+1.5=1.5V
Series voltage sources (batteries in this case) are added when their polarities are in the same direction, or series-aiding, and are subtracted when their polarities are in opposite directions, or series-opposing. Example....
arrangement to produce a larger voltage. Vs(tot) = VS1+Vs2+Vs3
Series-aiding
Series voltage source are added when their polarities are in the same direction, or series-aiding, and are subtracted when their polarities are in opposite directions. Vs(tot)=Vs1-Vs2+Vs3
Series-opposing
stays the same
Suppose the power suppy is doubled to 200 volts. The percentage of R2 ________ to the total resistance
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The algebraic sum of the voltages around any closed path in a circuit is equal to zero.
if the voltage (pressure) is doubled, the current flow will doubled.
The amount of current that flows is directly proportional to the voltage applied. Give an example...
if the resistance is doubled, the current flow will be reduced by half.
The amount of current that flows is inversely proportional to the resistance in circuit. Give an example...
Ammeters placed at four different locations in the series circuit read the same current value.
The current that flows in a series circuit is the same throughout the entire circuit. Give an example...
100 watts
The power consumed by a series circuit with 100 ohms of resistance and 100 volts applied is ______________.
PT=VsI PT=I2RT PT=V2s/RT
The total amount of power in a series resistive circuit is equal to the sum of the powers in each resistor in series.
4 volts
Three 2-volts batteries with their polarities in one direction are connected in series with a fourth 2-volts battery in the opposite direction. What is the net voltage?
The total resistance is the sum of each of the individual values. RT=R1+R2+R3+...+Rn Also you can physically change the positions of the resistors in the circuit without affecting the total resistance or the current.
Total Resistance
Current through any of the series resistors is the same as the total current.
Total current
True
Total current (IT) is the same value as current flowing through any resistor in a series circuit. True or False
If you know the total current, you can find the voltage drop across any of the series resistors by Ohm's law.
Vx=ITRx
the voltage drop across it is the same percetage of the applied voltage.
Whatever the percentafe i of an individual resistor to the total resistance,...
zero volts develop across the shorted resistor, the voltages across the remaining resistors and total current increases.
When a short condition develops across a resistor in a series circuit ________.
current through each resistor and each meter.
When an open occurs in a series circuit, ______ is zero amps.
voltages
When batteries are connected in eries with their polarities in the same direction, their ________ are additive.
Zero
When there is an open condition, such as an open seitch in a series circuit, the power dissipated by the circuit is ________ watts
True
When there is no restriction to current flow, a pressure difference does not exist. True or False
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When two or more voltage sources are in series, the total voltage is equal to the algebraic sum of the individual source voltages.
Wire clipping connecting two sections of a circuit can cause a short first and then an open by tripping a fuse.
Wire clipping connecting two sections of a circuit can cause _______ first and then ______ by tripping a fuse.
Kirchhoff's Voltage Law
_________ can be used to determine an unknown circuit value.