DC Final
Accurate troubleshooting of a parallel circuit cannot be performed with a voltmeter.
true
The total resistance of four resistors in parallel is always less than the smallest resistance.
true
A three-branch parallel circuit carries a total current of 1.2 mA. If I1 = 0.2 mA and I2 = 0.7 mA, then what is the value of I3?
0.3mA
A 250 μA current flowing through a 4.7 kΩ resistor produces a ________ voltage drop.
1.18 V
If three 75 W lamps are connected in parallel across a 125 V source, IT equals ________.
1.8A
Two 100 kΩ resistors are wired in series across a 20 V source. How much voltage does each resistor drop?
10 V
If 18 V and 6 V sources are connected in series opposing, what is the total voltage?
12 V
The total resistance of a three-branch parallel circuit is 76.92 Ω. If R1 = 100 Ω and R2 = 500 Ω, what is the value of R3?
140 Ohms
A 5.2 MΩ resistor, 1.2 MΩ resistor and 1 MΩ resistor are connected in parallel across a 15 V source. What is the total current if the 1.2 MΩ resistor opens?
2.41 uA
A two-branch parallel circuit contains these values: R1 = 1200 Ω, IT = 0.005 mA, I2 = 0.003 mA. What is the value of VR1?
2.4m V
If a 500 Ω, 1200 Ω and 10 kΩ resistor are connected in parallel across a 25 V source, how much current flows through the 1200 Ω resistor?
20.8mA
A 220 Ω 1/2 W resistor has burned open, so you look in your parts box to find a replacement. Although it is not good practice, which one of the following resistors could you use to repair the circuit?
220 Ω 1 W
When taking current measurements, it is extremely important not to accidentally place the meter across the voltage source.
True
The electrical symbol for voltage is ________.
V
Interpret the following mixed numbers and letters 3M3 on a resistor to the correct resistance of:
3300 Kilohms
If a 68 Ω, 33 Ω, 100 Ω and 47 Ω resistor are connected in series across a 9 V battery, the current equals ________.
36.3 mA
A 22 kΩ and 12 kΩ resistors are connected across a 68 V source. How is the voltage divided?
44 V and 24 V
A resistor with yellow, violet, orange and silver bands equals ________.
47 kΩ ± 10%
A resistor with yellow, violet, orange, and gold bands equals ________.
47 kΩ ± 5%
If the power dissipation in each of four parallel branches is 1 W, PT equals ________.
4W
If a 100 Ω, 220 Ω, and 330 Ω resistor are connected in series, total resistance equals ________.
650 Ω
If 5 A and 3 A enter a junction from two separate paths, how much current flows out of the junction?
8A
If twelve 1.5 MΩ resistors are connected in parallel across 50 V, RT equals ________.
0.125M ohms
In a three-resistor parallel circuit, R1 = 0.22 MΩ and R2 = 1 MΩ. If RT = 0.1166 MΩ, then what is the value of R3?
0.134M ohms
If 12 V and 17 V sources are wired in series aiding, what is the total supply voltage?
29 V
A resistor with orange, orange, red and gold bands has a value and tolerance of ________.
3.3 kΩ ±5%
If four 100 W lamps are connected in parallel across a 120 V source, what is the total current?
3.33A
A loaded voltage divider is a series-parallel circuit.
True
AC is often converted to DC with a power supply
True
Electromotive force is measured in volts.
True
Engineering notation is typically used in the expression of extremely large and small quantities in the electronics field.
True
If a 56 kΩ resistor carries 10 mA, it is safe to use a 10 W resistor.
True
If a circuit's resistance increases, its current decreases.
True
The current through any branch of a parallel circuit ________.
is inversely proportional to the branch resistance
If a 2.2 kΩ resistor and a 3.3 kΩ resistor are connected in parallel, RT equals ________.
less than 2.2k ohms
What type of resistor, used alone, could be used as a variable voltage-divider?
potentiometer
Which of the following is not a type of variable resistor?
potentiometer, thermistor photoconductive cell, they All are types of variable resistors.
Potentiometers and rheostats differ in that:
potentiometers utilize three terminals, while rheostats usually use only two terminals; potentiometers are used to vary voltages, while rheostats vary currents, and potentiometers utilize linear and nonlinear tapers, while rheostats usually utilize only linear tapers.
A(n) ________ is a material that has many free electrons.
Conductor
Voltage sources in series increase both voltage and current capacity.
False
According to Ohm's Law, if the voltage were to decrease while resistance remained the same, the current would
Decreases
Voltage and current are ________.
Directly Proportional
A Normally Open Push Button switch can carry current when not pushed.
False
A resistor color coded with yellow, violet and orange bands has a value of 4.7 kΩ.
False
Electrons have a positive charge.
False
If IR1 = 75 mA and IR2 = 12.7 mA in a two branch parallel circuit, IT = 85.7 mA.
False
If a circuit's resistance decreases, its current also decreases
False
If one branch of a parallel circuit opens, the total resistance decreases.
False
If the voltage applied to a circuit doubles, then power dissipation doubles
False
If three equal resistors are connected in parallel across 12 V, each resistor drops 4 V.
False
Maximum power is achieved when the load resistance is approximately two times the source resistance.
False
Negative charges move from the positive terminal to the negative terminal in an electrical circuit.
False
Power in a series-parallel resistor circuit is dissipated as:
Heat
Which is the correct formula for Ohm's Law?
I = V ÷ R
If voltage is 12 V and the resistance is color-coded brown-black-orange in Figure 3-1, what are the minimum and maximum possible currents?
IMINIMUM = 1 mA, IMAXIMUM = 1.5 mA
If the voltage is 15 V and resistance is color coded red-red-brown-silver in Figure 3-1, what are the maximum and minimum possible current?
IMINIMUM = 62.0 mA, IMAXIMUM = 75.8 mA
A formula that applies to a two-branch parallel circuit is ________.
IT = IR1 + IR2
As additional branch resistors are connected in a parallel circuit, ________.
IT increases and RT decreases
If one resistor opens in a parallel circuit, the total circuit resistance ________ and the total circuit current ________.
Increases, Decreases
Four resistors are connected in series across an 18 V source. Three resistors drop 0 V and one resistor drops 18 V. What's the trouble?
One resistor is open.
The symbol for electrical charge is ________.
Q
In solving series-parallel circuits using Ohm's law, first solve for:
RT
If the voltage across a circuit increases, ________.
The current Increases
A SPST switch is used to control one circuit.
True
If the current is constant, voltage and resistance are directly proportional.
True
If two resistors are in parallel, they drop the same voltage.
True
In a series circuit, the current is the same at every point in the circuit.
True
Kirchhoff's Voltage Law states that the algebraic sum of all the voltages around a closed path is zero
True
Resistance is the opposition to the flow of current.
True
The movement of free electrons through a conductor is called current.
True
The ohm is the basic unit of resistance.
True
The power rating for a resistor is mainly based on the physical size.
True
The total power dissipated by a parallel circuit can be found by adding the individual powers.
True
The total power dissipated in a series circuit equals the sum of the individual powers
True
Thevinizing a circuit creates an equivalent series circuit.
True
To measure the current through a resistor, place the ammeter so the current must pass through the meter.
True
Total power dissipated in a series circuit equals source voltage multiplied by current.
True
Two or more resistors connected in series form a circuit known as a voltage divider.
True
An analog meter has ________.
a needle and a scale to indicate the value
Every electrical circuit must contain ________.
a source, a load and a path
Any component that requires a source of power to function is called
an active component
Signals that vary continuously are called
analog signals
An ohmmeter should ________.
be placed across the resistor after the resistor has been disconnected from the circuit
To measure a circuit's source voltage, the voltmeter must ________.
be placed across the source
In order to measure the current in a circuit, an ammeter must ________.
be placed so the current must pass through the meter
A model of a complex electronic system is often simplified and represented as a
block diagram
If the current in a circuit equals 0 A, it is likely that the ________.
circuit is open
If one resistor opens in a parallel circuit, the total current ________.
decreases
In the American Wire Gauge sizes, as the numerical value of AWG goes higher, the cross-sectional area of the wire:
decreases.
If a 1/2 W resistor is used in the circuit in Figure 3-1, the current value ________.
depends upon the circuit's voltage and resistance
The ratio of the output of a circuit to the input is called
efficiency
The difference between electrical and electronic systems is
electrical deals with power while electronic deals with signals
The metric prefix μ (micro) is normally associated with ________ measurements.
extremely small
The difference between scientific and engineering notation is ________.
groupings of multiple of three digits, powers of ten representation, and single vs multiple digits before decimal point
If you want to measure a load voltage with a DVM, connect the meter ________.
in parallel with the load
On a resistor with numbers and letters, the position of the letter in the sequence represents:
the decimal point.
An insulator is a material with ________.
very few free electrons
What is the easiest, most practical measurement performed during troubleshooting?
voltage
If the measured circuit current is zero, it is likely that the ________.
voltage is turned off
Most DMMs will measure ________ ________ and
voltage, current, resistance
