Electronics 10% Flashcards
Two capacitors, each rated at 220 µF, are connected in parallel. The capacitance of the combination will be:
220µF
240µF
110µF
440µF
440µF
Two capacitors, each rated at 15 µF, are connected in series. The capacitance of the combination will be:
30µF
15µF
75µF
7.5µF
7.5µF
The fourth band of a four band resistor is marked in silver. This indicates a tolerance of:
25%
10%
20%
5%
10%
The third band of a four band resistor is marked in black. This indicates multiplier of:
10
1
100
1000
1
Two resistors, each measuring 15 Ω, are connected in series. The resistance of the combination will be:
30Ω
3Ω
15Ω
7.5Ω
30Ω
Two resistors, each measuring 220 Ω, are connected in parallel. The resistance of the combination will be:
220Ω
240Ω
110Ω
440Ω
110Ω
Resistor A is marked with the following colored bands: Red, Red, Red, Gold. The value of the resistor will be:
222 Ω 5%
2.2 kΩ 5%
22.2 kΩ 5%
333 Ω 5%
2.2 kΩ 5%
A battery of 24 V is connected across an unknown resistance. If a current of 0.5 A is supplied, which one of the following gives the value of the resistor?
6 Ω
48 Ω
12 Ω
24 Ω
48 Ω
An alternating current has a frequency of 2 kHz. Which one of the following gives the time for one complete cycle?
0.5 ms
1 ms
5 ms
2 ms
0.5 ms
The symbol used to denote charge in an electrical circuit is:
V
E
Q
C
Q
In a purely inductive circuit:
voltage leads current by 90°
voltage and current are in phase (0°)
current leads voltage by 90°
voltage lags current by 45°
voltage leads current by 90°
After which time constant can a capacitor be considered to be fully charged?
fifth
third
first
seventh
fifth
As a capacitor is being charged, current flowing into the capacitor will:
cannot tell
increase
remain the same
decrease
decrease
The electrical energy consumed by a coil is stored in the form of:
an electrical field
an electrostatic field
a magnetic field
a force field
a magnetic field
When a transformer secondary lead has been connected to a middle loop that is not an end connector, it is called a:
center-tapped secondary
multiple winding secondary
multiple-tapped secondary
single winding secondary
center-tapped secondary
Two inductors, each rated at 6.8 mH, are connected in parallel. The inductance of the combination will be:
16.8 mH
3.4 mH
6.8 mH
13.6 mH
3.4 mH
A loss-free transformer has 1200 primary turns and 300 secondary turns. If the primary winding is connected to a 200 V AC supply which one of the following gives the secondary voltage:
800 V
100 V
200 V
50 V
50 V
Two inductors, each rated at 22 mH, are connected in series. The inductance of the combination will be:
11 mH
22 mH
33 mH
44 mH
44 mH
In a purely capacitive circuit:
voltage leads current by 90°
voltage lags current by 45°
voltage and current are in phase (0°)
current leads voltage by 90°
current leads voltage by 90°
ICE
In an RLC circuit, Z represents:
Inductive reactance
Total impedence
Total resistance
Capacitive reactance
Total impedence
Under normal conditions a diode conducts current when it is:
reverse-biased
saturated
avalanched
forward-biased
forward-biased
The arrow on a schematic symbol for a diode points to the:
direction of electron flow
cathode
Anode
ground
cathode
An N-type semiconductor material:
is intrinsic.
has pentavalent impurity atoms added.
has trivalent impurity atoms added.
requires no doping.
has pentavalent impurity atoms added.
(known as doping)
An ideal diode presents a(n) ________ when reversed-biased and a(n) ________ when forward-biased.
short, short
open, open
short, open
open, short
open, short
The term bias in electronics usually means:
the value of DC voltages for the device to operate properly.
the status of the diode.
the condition of current through a PN junction.
the value of AC voltage in the signal.
the value of DC voltages for the device to operate properly.
The collector current in a bipolar junction transistor is 2 mA when the base current is 0.1 mA. Which one of the following gives the emitter current?
1.9 mA
20 mA
0.7 mA
2.1 mA
2.1 mA
In normal (conducting) operation, the voltage that will appear between the base and emitter of an NPN bipolar junction transistor will be approximately:
1.05 V
0.65 V
0.25 V
0.15 V
0.65 V
(Base/emitter voltage drop)
Which one of the following gives the relationship between the three currents flowing in an NPN bipolar junction transistor?
IC = IB + IE
IB = IE + IC
IE = IB + IC
IE = IB + IC
(Emitter current = Base current + Collector current)
The three terminals of a bipolar junction transistor are known as:
Emitter, base, collector
Source, gate, drain
Drain, base, collector
Emitter, gate, collector
Emitter, base, collector
In a semiconductor diode, the depletion region is removed when:
The diode is in its reverse non-conducting state
The cathode is more positive than the anode
The diode is in its forward conducting state
There is no potential difference between the anode and cathode
The diode is in its forward conducting state
The primary function of the bias circuit is to:
hold the circuit stable at the designed Q-point(operating point)
When a conductor interacts with a magnetic field, the induced current sets up a magnetic field that opposes the interaction. This is known as
Lenz’s Law
If a 3-input OR gate has eight input possibilities, how many of those possibilities will result in a HIGH output?
7
000=0
everything else would have a 1 so results in a 1 output
The output of an exclusive-OR gate is HIGH if:
-the inputs are unequal
-all inputs are LOW
-none are correct
-all inputs are HIGH
-the inputs are unequal
What does the small bubble on the output of the NAND gate logic symbol mean?
-The output is the
arithmetic sum of the
inputs
-The output is inverted
-The output is the absolute
value of the inputs
-None are correct
-The output is inverted
The output of a NOR gate is HIGH if:
-all inputs are HIGH
-any input is LOW
-all inputs are LOW
-any input is HIGH
-all inputs are LOW
The Boolean expression for a 3-input AND gate is:
X = A · B · C
X = A + B + C
X = A - B - C
X = A ⊕ B ⊕ C
X = A · B · C
A 2-input NAND gate output will be LOW if the inputs are:
00
10
01
11
11
00=1
10=1
01=1
11=0
Which of the following logical operations is represented by the + sign in Boolean algebra?
AND
OR
inversion
complementation
OR
The output of an OR gate with three inputs, A, B, and C, is LOW when:
A = 1, B = 1, C = 1
A = 0, B = 1, C = 1
A = 0, B = 0, C = 1
A = 0, B = 0, C = 0
A = 0, B = 0, C = 0
A device used to display one or more digital signals so that they can be compared to expected timing diagrams for the signals is a:
DMM
frequency counter
logic analyzer
spectrum analyzer
logic analyzer
The output of an AND gate with three inputs, A, B, and C, is HIGH when:
A = 1, B = 1, C = 0
A = 1, B = 0, C = 1
A = 1, B = 1, C = 1
A = 0, B = 0, C = 0
A = 1, B = 1, C = 1
All inputs High
What would the inputs have to be on a 3 input OR gate to get a low out?
A. All low
B. All high
C. 2 lows 1 high
D. 2 high 1 low
A. ALL LOW
Solve this binary equation. Answer in a decimal number form. 11011+1111=
A. 42
B. 54
C. 15
D. 101010
A. 42
A few capacitors are in parallel. Calculate the total capacitance. The capacitor values are1uF, 2uF, 3uF, and 4uF. The total capacitance is:
A. 10 uF
B. 5 uF
C. 1 uF
D. 01 uF
A. 10 uF
Use same method as resistors in series .
1µF + 2µF + 3µF + 4µF = 10µF
If a 4AH battery were replaced with a 2 AH with the same voltage rating, what would the result be?
A. Shorter run time.
B. Longer run time
C. Same run time
D. It would overheat the charging circuit
A. A SHORTER RUN TIME
A Nicad battery normally has:
A. 1.3 V per cell
B. 1.2 V per cell
C. 1.5 V per cell
D. 1.0 V per cell
B. 1.2 V per cell
Nickel-cadmium cells have a nominal cell potential of 1.2 volts (V).
10 to the minus 6 power is the prefix for which of the following?
A. Milli
B. Mega
C. Micro
D. Pico
C. MICRO
Which of the following is defined as volatile memory?
A. ROM
B. Flash
C. Stable
D. RAM
D. RAM
a. ROM non-volatile memory include read-only memory
b. Flash Flash memory is a non-volatile computer storage chip that can be electrically erasedand reprogrammed.
c. Stable
d. RAM The most widely used form of primary storage today is a volatile form of random access memory (RAM), meaning that when the computer is shut down, anything contained in RAM is lost.
Which of the following is the objective of a band-pass filter?
A. Allow a range of frequencies between an upper and lower cutoff point to pass through.
B. Allow a range of frequencies below a upper cutoff frequency to pass through.
C. Allow a range of frequencies above a lower cutoff frequency to pass through.
D. Allow a range of frequencies above an upper cutoff frequency and below a lower cutofffrequency to pass through.
A. Allow a range of frequencies between an upper and lower cutoff point to pass through.
In order for a basic power supply to operate correctly, which of the following is true?
A. The transformer must follow the regulator.
B. The rectifier must follow the filter.
C. The rectifier must follow the transformer.
D. The regulator must be before the filter.
C. The rectifier must follow the transformer.
Calculate the total inductance of two 40mH inductors in parallel.
A. 20 mH
B. 80 mH
C. 40 mH
D. 60mH
A. 20 mH
Calculate the total resistance of these resistors in parallel. 100 ohm, 3K ohm, 10K ohm.
A. 14100 ohms
B. 13100 ohms
C. 95 ohms
D. 100 ohms
C. 95 ohms
A few capacitors are in parallel. Calculate the total capacitance. The capacitor values are1uF, 2uF, 3uF, and 4uF. The total capacitance is:
A. 10 uF
B. 5 uF
C. 1 uF
D. 01 uF
A. 10 uF
Use same method as resistors in series .
1µF + 2µF + 3µF + 4µF = 10µF
Which of the following is best determined by using an oscilloscope?
A. The relationship between AC and DC in a circuit.
B. The amount of AC current in a circuit.
C. The amplitude of a DC signal.
D. The voltage dropped across a resistor.
A. The relationship between AC and DC in a circuit.
Which of the following occurs when batteries are connected in series?
A. The current capability increases.
B. The voltage provided will increase.
C. The smaller battery will explode.
D. The voltage provided will decrease.
b. The voltage provided will increase.
Connecting batteries in series increases voltage
Which of the following is the objective of a band-pass filter?
A. Allow a range of frequencies between an upper and lower cutoff point to pass through.
B. Allow a range of frequencies below a upper cutoff frequency to pass through.
C. Allow a range of frequencies above a lower cutoff frequency to pass through.
D. Allow a range of frequencies above an upper cutoff frequency and below a lower cutofffrequency to pass through.
A. Allow a range of frequencies between an upper and lower cutoff point to pass through.
The decimal number 255 is equivalent to which of the following Hexadecimal numbers?
A. AA
B. 100
C. FF
D. FA
C. FF
255/15=15 remainder 15
In Hex 15 is F, Therefore 255 in Hex is FF
Which of the following is the unit of measure for capacitance?
A. Henrys
B. Farads
C. Working volts
D. Coulombs
B. FARADS
Which of the following is the equivalent resistance of two 20 Ohm resistors in parallel in series with a 10 Ohm resistor?
A. 30 Ohms
B. 15 Ohms
C. 50 Ohms
D. 20 Ohm
D. 20 OHMS
Parallel: 1/((1/20)+(1/20)) = 10 Ohms
Add 10 Ohms from above with the 10 Ohm series resistor answer is 20 Ohms
A heating element uses 90 Watts of power and has a resistance of 1kΩ. Calculate the current through the heating element.
A. 0.09 milliamps
B. 0.300 milliamps
C. 300 milliamps
D. 9 milliamps
C. 300 milliamps
Power = I² X R B.
90W = I² X 1KΩ (90/1000) = I²
.09 = I²
.3 = I
Convert this number to decimal 4AF.
A. 1200
B. 1199
C. 1015
D. 1315
B. 1199
(416^2)+(A16^1)+(F*16^0)
=(4256)+(1016)+(15*1)
=1024+160+15=1199
An Oscilloscope reads 10 volts peak to peak. What is the RMS voltage?
A. 707 VRMS
B. 7.07 VRMS
C. 3.54 VRMS
D. 1.414 VRMS
C. 3.54 VRMS
Peak Voltage X .707 = RMS voltage
5V X .707 = 3.54 VRMS
A Triac is used to switch:
A. DC power
B. AC power
C. AC or DC power
D. FET gate current
B. AC power
the TRIAC a very convenient switch for AC circuits
A transformer has 1968 primary windings and 492 secondary windings (4:1) and the input current is 1 amp. Output current is?
A. 250 mA
B. 4 A
C. 500 mA
D. 2 A
B. 4 A
(Np/N/s) = (Ep/Es) = (Ip/Is)
(4/1) = (1/x) cross multiply 4=x