Robotics Final
A sine wave with a period of 2 ms is changing at a faster rate that a sine wave with a period of
.0025 ms
A power factor of 1 indicates that the circuit phase angle is
0
What is the inductive reactance of an inductor that drops 12 Vrms and carries 50m
240Ω
When R=Xc the phase angle is
45°
The duty cycle of a square wave is
50%
is the reciprocal of impedance and is expressed as Y= 1/Z
Admittance
The rms and average value of a sine wave are the same?
False
Impedance is the total opposition to sinusoidal current expressed in ohms.
True
In a series RC circuit, the voltage across the resistance is
in phase with the current
When the frequency of the voltage applied to a series RC decreased, the phase angle
increases
in a series RC Circuit, the voltage across the capacitor is
lagging the resistor voltage 90°
Energy sources are normally rated in
volt-amperes
The average value of a 10V peak sine wave over one complete cycle is
0 V
What is one time constant for 10mH inductor connected in series with a 47 kΩ resistor?
0.213μS
What is the maximum current in a 12 mH inductor if is connected in series with a 10 KΩ resistor?
1.5 mA
If a load is purely inductive and the reactive power is 10 VAR, the apparent is ________.
10 VA
Two series resistors are connected to an ac source. If there is 6.5 V rms across one resistor and 3.2 V rms across the other , the peak source voltage is
13.72 V
If VR is 10 V and VL is 10V in a series PRL circuit, the source voltage equals:_______.
14.14 V
In a series RC circuit, 10V rms is measured across the resistor and 10 V rms is also measured across the capacitor. The rms voltage is
14.14 V
If the peak value of a sine wave is 20 V, the rms value is
14.14V
If a 27 mH inductor has a reactance of 5.5 kΩ, the frequency equals _______.
32.4 kHz
One sine wave has a positive-going zero crossing 10° and another sine wave has a positive- going zero at 45° . The phase angle between the two waveforms is
35°
How many time constants will it take to completely collapse an inductor's magnetic field?
5
If the rms current through a 10kΩ resistor is 5 mA, the rms voltage drop across the resistor
50V
When a sine wave has a frequency of 60 Hz.,in 10 s it goes through
600 cycles
When the frequency of the voltage applied to a series RC circuit is increased, the impedance
Decreases
A low-pass filter passes high frequencies and blocks other frequencies.
False
If the inductance increases in an RL filter, the cutoff frequency increases.
False
Inductive reactance decreases as frequency increases.
False
The impedance of a series RL circuit is found by adding the values of XLand R.
False
The impedance of an RL series circuit varies inversely with the frequency.
False
The overall phase angle of a parallel circuit with a resistance of 20Ω and an inductive reactance of 25kΩ would be nearly 90°
False
The total inductance of two parallel inductors equals the sum of their inductance values.
False
The voltage and current are in phase in an inductive circuit.
False
True power for an inductor is measured in VAR rather than watts.
False
is realized by taking the output across the capacitor, just as in a lag circuit
Low-pass circuit
To decrease the phase angle below 45°, the following conditions must exist:
R>Xc
A high-pass filter high frequencies and blocks low frequencies?
True
Inductors in series or parallel combine just like resistors in series and parallel.
True
The energy stored in an inductor's electromagnetic field is produced by the inductor's current.
True
The number of radians in 360º is 2π.
True
The phase angle is the phase difference between the total current and the source voltage.
True
The term cosθ is called the power factor and is stated as PF = cosθ
True
The difference between alternation (ac) and direct current (dc) is
ac changes direction and dc does not
Power in an RL circuit can be measured as:
all of these apparent power (Pa), reactive power (Pr), true power (Ptrue)
The range of frequencies that is considered to be passed from the input to the output of circuit is call:
bandwidth
In a series RC circuit when the frequency and the resistance are doubled, the impedance
cannot be determined without values
If an inductor has an ac current flowing through it, the magnetic field is ________
constantly changing
In an inductive circuit, the ______ lags the _________.
current, voltage
is a circuit that generates a periodic waveform and is an important circuit for many electronic systems?
oscillator
An RL high pass filter takes its output across:
the parallel inductor
The period of a 60 Hz sine wave is 16.7ms
true
Which of the following is typically most important of the three types of power in terms of work being done.
true
During each cycle, a sine wave reaches a peak value
two times
Reactive power (Pr) in an inductor is defined as the rate at which an inductor stores or returns energy and is measured in
volt-ampere reactive
If the bandwidth of a certain low-pass filter is 1 khz, the cutoff frequency is
1000 Hz
The average value half-cycle value of a sine wave with a 20 V peak is
12.74V
Connecting a _________ inductor in _______ with a 100 mH inductor produces a 65 mH inductance.
185.7 mH, parallel
If the resistive current is 2A and the inductive current is 2A in a parallel RL circuit, total current is
2.828 A
What is the total inductance if a 50mH inductor is connected in series with a 15 mH inductor?
65 mH
If a 50 mH inductor operates at 22 kHz, XL equals
6908Ω
Inductors ________
block direct current
The total series capacitance is always less than the smallest?
capacitance
When the frequency of the source voltage is increased, the impedance of a parallel RC circuit
decreases
An advantage of a three-phase induction motor is that it
does not require starting windings
is implemented by taking the output across the resistor, as in in lead circuit.
high-pass circuit
The relationship between volt-amperes and true power or watts. Volt-amperes multiplied range of frequencies is called Power Factor.
true
A 10 kHz pulse waveform consists of pulses that are 10 µs wide. It's duty cycle is
10%
A sine wave with a frequency of 12 kHz is changing at a faster rate than a sine wave with a frequency of
10,000Hz
If the true power is 10 W and the reactive power is 10 VAR, the apparent power is __________.
14.14VA
What is the inductance of a 20 mH inductor connected in parallel with a 50 mH inductor.
14.29 mH
If the peak value of a sine wave is 10 V, the peak to peak value is
20V
The instantaneous value of a 15 A peak sine wave at 32° from it's positive-going zero crossing is
7.95A
What is the total inductance of a 14mH, 22mH and 45mH inductor connected in series?
81 mH
RC circuits do not use ohm's law.
False
A phase shift circuit in which the output voltage, taken across the capacitor, lags the input voltage by a specified angle is called:
RC lag circuit
When a DC voltage is first applied to an inductor, the initial circuit current is zero.
True
Do iron-core inductors or air-core inductors generally have a larger inductance?
iron-core
The difference in the synchronous speed of the stator field and the rotor speed of a motor is called
slip
If two inductors are connected in series AC circuit, which inductor drops more voltage?
the larger inductance
In an RL filter circuit, the cutoff frequency is defined as the frequency at which:
the output voltage drops to 70% of maximum
