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WorksheetsDC review 2 Components
Total questions: 83
Worksheet time: 45mins
What does LED stand for?
Laser Emitting Diode
Light Energy Diode
Luminous Electric Device
Light Emitting Diode
What is the typical wavelength range visible to humans?
500 to 800 nanometers
300 to 600 nanometers
400 to 700 nanometers
600 to 900 nanometers
What type of light does a TV remote's LED emit?
Visible Red
Infrared
Ultraviolet
Blue
What is the purpose of the flat edge on an LED?
To improve light emission
For aesthetic purposes
To indicate the anode side
To indicate the cathode side
What happens when a voltage is applied across an LED?
It produces a magnetic field
It produces light
It produces heat
It produces sound
What is the function of a resistor in an LED circuit?
To decrease the voltage
To increase the voltage
To store electrical energy
To protect the LED by limiting current
What does the color of an LED depend on?
The color of the case
The wavelength of the photon it emits
The shape of the LED
The amount of voltage applied
What are SMD LEDs used for?
In light bulbs for compact designs
In remote controls only
For high power applications only
For outdoor lighting only
How can the brightness of an LED be controlled?
By changing its color
By using multiple LEDs
By varying the current
By using a larger battery
What is the minimum voltage required for a red LED to start conducting?
1.1 volts
2 volts
1.7 volts
0.5 to 0.7 volts
What type of switch is this circuit symbol?
SPST
SPDT
DPST
DPDT
PTM
What package of switch is this?
Slide switch
Rocker switch
Toggle switch
Micro switch
Key switch
What type of switch is this circuit symbol?
SPST
SPDT
DPST
DPDT
PTM
What package of switch is this?
Slide switch
Reed switch
Toggle switch
Micro switch
Key switch
What type of switch is this circuit symbol?
SPMT
SPDT
DPST
DPDT
PTM
What package of switch is this?
DIP Switch
Push Switch
Slide Switch
Rocker Switch
Key Switch
What type of switch is this circuit symbol?
SPMT
PTM
DPST
SPMT
PTB
What package of switch is this?
DIP Switch
Rotary Switch
Slide Switch
Rocker Switch
Key Switch
What type of switch is this circuit symbol?
SPST
SPDT
DPST
DPDT
PTM
What package of switch is this?
Slide switch
Rocker switch
Toggle switch
Micro switch
Key switch
What type of switch is this circuit symbol?
SPST
SPDT
DPST
DPDT
PTM
What package of switch is this?
Toggle Switch
Push Switch
Slide Switch
Rocker Switch
Key Switch
What type of switch is this circuit symbol?
SPMT
PTM
DPST
SPMT
PTB
Will the light bulb in this circuit and why/why not?
yes, because it has two batteries
no, because the switch is open
yes, because it is in a circuit
no, because the bulb is burned out
In which of these circuits the bulb will light up?
Circuit C
Circuit B
Both B and C
Circuit A
What type of switch is this?
Toggle
Rocker
Slide
Key
What type of switch is this?
Slide
Push to Make
Tilt
Rocker
What type of switch is this?
Key
Micro
Tilt
Rocker
A_______________ switch is one that only changes state when pressed or actuated. When the pressure is released, the switch will return to the normal position/ state.
Momentary
Maintained
A _______________ switch is one which is switched on by the user and then remain on until switched off again.
Momentary
Maintained
This is a closed switch.
True
False
This is a closed switch.
True
False
A switch is an input device.
True
False
What type of switch is this?
Toggle
Rotary
Rocker
Slide
What will happen when the switch closes.
Current will flow and the LED will switch off.
Current will flow and the LED will switch on.
No current will flow because the resistance is too high.
The LED will explode.
What is a Switch?
a device which is designed to interrupt the current flow in a circuit.
a device which is designed to interrupt the fluid in a circuit.
a device which is designed to oppose the current flow in a circuit.
a device which is designed to resist the current flow in a circuit.
Every electrical and electronics application uses at least one switch to perform ON and OFF operation of the device.
T/F
True
False
A switch can make or _____ an electrical circuit.
take
break
add to
make
Switches are a part of the control system and without it, control operation cannot be achieved.
T/F
false
true
A switch can perform two functions, namely fully __ (by closing its contacts) or fully ___ (by opening its contacts).
(a)
When the contacts of a switch are closed, the switch creates a (a) path for the current to flow
What type of switch is this
(a)
The two important characteristics of a switch are its _____ and _____
(a)
A characteristic of a switch is its action i.e., whether it is a Momentary or Latched action
T/F
false
true
A _______ switch definition is; a switch that doesn’t require continuous compression to stay on.
momentary
latching
float
What type of switch does a drill have?
(a)
Basically, Switches can be of two types
(pick 2)
float
gate
Mechanical
Electronic
Momentary Switches (like push buttons, for example) are used to make momentary contact (for a brief time or as long the button is pressed).
T/F
false
true
If the number of poles or throws are greater than 2, then the number is often directly used. For example, a three pole six throw switch is often represented as 3P6T.
T/F
true
false
(a) Switches, maintain the contact until it is forced to the other position.
How does a Stepper Motor move ?
A. Electrical Pulse
B. Continuous Applied Voltage
C. Alternates from A and B
A pulse can be produce by which means ?
A. Microprocessor
B. Timing Logic
C. Toggle Switch
D. All of the above
Which of the following is not a type of stepper motor?
A. Variable Reluctance
B. Hybrid
C. Magnetic
D. Lead-Screw
Which of the following is not a component of a stepper motor?
A. Windings
B. Rotor and Stator
C. Commutator
D. Brush
E. Both C and D
What is the difference between full-step and half-step?
A. In full-step two phases are on and in half-step only one phase is on.
B. More resonance is evident in half-step
C. More power required for full-step
D. Half-step offers better resolution
Which of the following is NOT an advantage of stepper motors?
A. Cost-efficient
B. Maintenance-free
C. No feedback
D. More complex circuitry
With a stator having 8 teeth and a rotor having 6 teeth, what step angle will an application be able to achieve?
A. 15°
B. 51°
C. 20°
D. 105°
A variable reluctance stepper motor is constructed of .................. material with salient poles.
(a) paramagnetic
(b) ferromagnetic
(c) diamagnetic
(d) non-magnetic
In a three-stack 12/8-pole VR motor, the rotor pole pitch is
(a) 15º
(b) 30º
(c) 45º
(d) 60º
A stepper motor having a resolution of 300 steps/rev and running at 2400 rpm has a pulse rate of— pps.
(a) 4000
(b) 8000
(c) 6000
(d) 10,000
A stepping motor is a .................. device.
(a) mechanical
(b) electrical
(c) analogue
d) incremental
The rotational speed of a given stepper motor is determined solely by the
(a) shaft load
(b) step pulse frequency
(c) polarity of stator current
(d) magnitude of stator current.
Which of the following phase switching sequence represents half-step operation of a VR stepper motor ?
(a) A, B, C, A .......................
(b) A, C, B, A .......................
(c) AB, BC, CA, AB .......................
(d) A, AB, B, BC .......................
How does a Stepper Motor move ?
A. Electrical Pulse
B. Continuous Applied Voltage
C. Alternates from A and B
A pulse can be produce by which means ?
A. Microprocessor
B. Timing Logic
C. Toggle Switch
D. All of the above
What is the difference between full-step and half-step?
A. In full-step two phases are on and in half-step only one phase is on.
B. More resonance is evident in half-step
C. More power required for full-step
D. Half-step offers better resolution
What criteria’s are necessary to consider when selecting a stepper motor?
A. Mechanical Motion.
B. Inertial Load
C. Speed Requirements
D. All of the above
If an application using a stepper motor required feedback, which device would be needed to accomplish this?
A. Counter
B. Encoder
C. Linear Guide
D. Commutator
A stepping motor is a ____________ device.
a) Mechanical
b) Electrical
c) Analogue
d) Incremental
The rotational speed of a given stepper motor is determined solely by the
a) Shaft load
b) Step pulse frequency
c) Polarity of stator current
d) Magnitude of stator current.
Which of the following phase switching sequence represents half-step operation of a VR stepper motor ?
a) A, B, C,A……..
b) A, C, B,A…….
c) AB, BC, CA, AB……..
d) A, AB, B, BC……..
A stepper motor may be considered as a ____________ converter.
a) Dc to dc
b) Ac to ac
c) Dc to ac
d) Digital-to-analogue
In permanent magnet stepper motor, the direction of motor is _____ to the directions of the current flowing in winding.
(a) dependent.
(b) reverse.
(c) independent.
(d) none of the above.
When the motor speed of the stepper motor increases, the torque will
(a) increases.
(b) remain same.
(c) decrease.
(d) none of the above.
The stepper motor has full torque at
(a) full speed.
(b) normal speed.
(c) zero speed.
(d) all speed.
The stepper motor is used in
(a) computer printers.
(b) robotics.
(c) clocks.
(d) all of the above.
The hybrid stepper motor is designed to provide
(a) highest speed.
(b) better efficiency.
(c) constant speed.
(d) highest starting torque.
Wave excitation of a stepper motor results
(a) microstepping
(b) half-stepping
(c) increased step angle
(d) reduced resolution.
the relationship between the step number and the step angle in a stepper motor
Step number (S) = 360° / θs
Step number (S) = 360° * θs
Step number (S) = 360° + θs
Step number (S) = 360° - θs
The torque exerted by the rotor magnetic field of a PM stepping motor with unexcited stator is called ..................torque.
(a) reluctance
(b) detent
(c) holding
(d) either (b) or (c)
In a stepper motor the detente torque means
maximum of the static torque with the phase winding excited.
minimum of the static torque with the phase winding unexcited.
minimum of the static torque with the phase winding excited.
maximum of the static torque with the phase winding unexcited.
stepper motors are mostly used for
a) high power requirements
b) control system applications
c) very high speed of operation
d) very low speed of operation
A stepper motor
A. is a two phase induction motor
B.is a kind of rotating amplifier
C.is an electromagnetic transducer used to convert an angular position of shaft into electrical signal
D.is an electromechanical device which actuates a train of step angular movements in response to a train of input pulses on one to one basis
