CET Practice Exam A
An inductor in an electronic circuit: A. resists AC current flow. B. appears capacitive to AC current. C. reduces DC power dissipation. D. is a near short to AC current.
A. resists AC current flow.
When heated or cooled, a _____ emits a voltage. A. thermocouple B. thermometer C. thermostat D. thermocline
A. thermocouple.
Class AB operation of an audio amplifier means that current flows through the active device (tube, transistor, FET, IC) for ____ degrees of the input signal wave. A. 360 B. more than 180 but less than 360 C. 45 but less than 180 D. 90
B. more than 180 but less than 360
Laminations used for the core of a transformer: A. must physically make metal to metal contact with the adjacent laminations. B. must be insulated from each other. C. increase eddy currents. D. reduce counter emf in the windings.
B. must be insulated from each other.
Solder flux mainly: A. removes foreign material on the soldering iron. B. removes oxides on metals to be soldered. C. controls the temperature of the solder. D. causes conductor-to-solder-to-conductor chemical adhesion.
B. removes oxides on metals to be soldered.
When soldering high voltage connections: A. it is important that a thermal shunt be in place. B. use a minimum of solder. C. leave the terminal with a smooth and rounded covering of solder. D. leave the connection with rough solder tips.
B. use a minimum of solder.
An antenna that is longer than another: A. will have a higher resonant frequency. B. will have a lower resonant frequency. C. has a higher Q. D. delivers higher power.
B. will have a lower resonant frequency.
A power supply whose output voltage does not change whether the load is light or heavy, would have what percent of regulation? A. 100 B. 50 C. 20 D. 0
D. 0
Which frequency will have a higher loss when using coaxial cable transmission line? A. 550 kHz B. 27 MHz C. 470 MHz D. 1 GHz
D. 1 GHz
Audio signals, such as the output from DVD players, satellite receivers and preamplifiers, usually are of what amplitude for input to a TV, modulator or other equipment? A. 100 microvolts peak-to-peak B. 1000 microvolts peak-to-peak C. 1 millivolt peak-to-peak D. 1 volt peak-to-peak
D. 1 volt peak-to-peak
I = 1 amp, R= 10,000 ohms. What is the value of the voltage? A. 1 volt B. 10 volts C. 100 volts D. 10,000 volts
D. 10,000 volts
What is the ripple frequency of a full-wave single phase bridge rectifier operated at 60Hz? A. 180 Hz B. 90 Hz C. 360 Hz D. 120 Hz
D. 120 Hz
Which of these would you normally choose to cause an LED to light? A. 3 mV AC B. 3 mV DC C. 30 mV DC D. 3 V DC
D. 3 V DC
Which of the below would be considered "basic" components of a non switching power supply? A. Zener, regulator, transformer, filter B. Regulator, diodes, AC power, load C. Transformer, bridge, capacitor, load D. Filter, regulator, rectifier, transformer
D. Filter, regulator, rectifier, transformer
What should be used first to clean a corroded plated soldering iron tip? A. Coarse emery cloth while cold B. Wet sponge with acid core solder after heating C. File D. Flux, cloth after heating
D. Flux, cloth after heating
Which of these signal parameters does a spectrum analyzer show? A. Current and phase B. Leakage capacitance C. Video color signal separation D. Magnitude and frequency
D. Magnitude and frequency
A Triac in a power control circuit: A. provides regulation. B. limits surges. C. acts as a fuse. D. acts as an on/off switch
D. acts as an on/off switch
Using a resistor instead of an inductor in a power supply pi filter: A. is less expensive. B. is less efficient. C. does not fi lter the AC as well. D. all of the above.
D. all of the above.
When working with and testing lead-acid batteries: A. wear eye protection goggles if battery caps are off. B. short between terminals only if in a well ventilated area. C. when charging, keep room closed off. D. always wear eye protection, never cause a spark and charge in a ventilated room.
D. always wear eye protection, never cause a spark and charge in a ventilated room.
The digital method of representing characters by using combinations of zeroes and ones is called: A. decimal. B. alpha-beta. C. duplex. D. binary.
D. binary.
The audio detector circuit in an AM radio most commonly is a: A. discriminator circuit. B. bridge circuit. C. transistor. D. diode
D. diode.
A ______ is a reference antenna that all other antennas with gain are compared to. A. Yagi B. omni C. mast D. dipole
D. dipole
When using fiber optic to transfer a signal, the light must: A. be visible. B. be LED generated. C. be between 3 GHz and 30 GHz. D. enter the "cone of acceptance."
D. enter the "cone of acceptance."
A high frequency antenna ______ than a low frequency one. A. is thicker B. is shorter C. has more gain D. is longer
D. is longer
The telephone communication term "Cellular" refers to: A. undefined telephone radio channels. B. a provider trade name. C. Caller Environment Lone Line service. D. small geographic areas covered by each base station.
D. small geographic areas covered by each base station.
The time required to discharge a capacitor depends on the __________ across its terminals. A. the total capacitance B. the total resistance C. the total inductance D. the combination of LRC
D. the combination of LRC
Decimal 164 would appear as _____in binary? A. 10010101 B. 10100100 C. 10001111 D. 01110100
B. 10100100
Doubling the power in a transmitter output signal is a ____ dB gain. A. 1 B. 3 C. 6 D. 10
B. 3
Soldering stations used for electronics circuit-board work have historically been (approximately): A. 5 watts. B. 30 watts. C. 100 watts. D. 250 watts.
B. 30 watts.
A resistor has color stripes yellow, violet, violet, silver. It is: A. 46 MegOhm +/- 10%. B. 470 MegOhm +/- 10%. C. 37 MegOhm +/- 10%. D. 48 kOhm +/- 5%.
B. 470 MegOhm +/- 10%.
he ripple frequency for a half wave rectifier operating from 60 Hz electrical power is: A. 30 Hz. B. 60 Hz. C. 120 Hz. D. 240 Hz.
B. 60 Hz.
A byte is: A. 4 bits. B. 8 bits. C. 16 bits. D. 32 bits.
B. 8 bits.
What specification should NOT be of concern regarding wire conductors? A. Resistance B. Capacitance C. Length D. Cross sectional are
B. Capacitance
If a class A differential amplifi er is using only one of its two possible inputs, what will the output signal shape be? A. Zero B. Exactly the same as the one input C. Equal in amplitude and frequency to the input D. Smaller than if two in-phase input signals were applied
B. Exactly the same as the one input
A free-running oscillator is also called a monostable multivibrator. A. True B. False
B. False
Permanent, non-volatile, non-removable data storage in a computer is: A. RAM. B. ROM. C. Flash. D. Optical disk.
B. ROM.
Carbon microphones are much like variable: A. Capacitors. B. Resistors. C. Thermistors. D. Inductors.
B. Resistors.
Which motor maintains a constant speed with changing loads? A. Series B. Shunt C. Servo D. Buck-boost
B. Shunt
An inductor opposes any change in: A. voltage. B. current. C. frequency. D. reactance.
B. current.
If you increase the value of a capacitor, the capacitive reactance will: A. increase. B. decrease. C. depend on connected components. D. not be affected by the value.
B. decrease.
A disadvantage of LCD (liquid crystal display) is: A. high current demands. B. environmental temperature sensitivity. C. slow reactance to input. D. vibration sensitivity limitations.
B. environmental temperature sensitivity.
If an RF signal voltage is reduced by 6 dB, it is then: A. 25% less. B. half the original size. C. 75% less. D. not changed in voltage level.
B. half the original size.
An autotransformer: A. has the secondary unattached to the primary. B. has a single winding. C. uses a core winding. D. uses a buck-boost coil.
B. has a single winding.
With a given filter type, pure filtering is easiest with: A. low frequencies. B. high frequencies. C. mid frequencies. D. any frequency.
B. high frequencies.
With + voltage to drain or source and a - voltage to the gate on an N channel JFET, internal resistance of the JFET will be: A. low. B. high. C. high to drain, low to source. D. low to source, high to drain.
B. high.
In checking a capacitor to see if it is shorted, open or leaky, you would use the ___ ohm meter range. A. lowest B. highest C. You can't check a capacitor this way. D. You will ruin the ohmmeter unless the capacitor is charged.
B. highest
A Logic Probe: A. injects signals into logic circuits. B. indicates high and low voltage conditions. C. measures dB levels. D. displays voltage levels on an analog scale.
B. indicates high and low voltage conditions.
The capacitor in a power supply capacitive filter: A. is in series with the load. B. is in parallel with the load. C. requires a serial choke. D. must be in parallel with a choke coil.
B. is in parallel with the load.
A series DC motor, with no load: A. tends to stop or not start. B. may be damaged by excessive speed. C. reverses direction. D. becomes an AC generator.
B. may be damaged by excessive speed.
Using the R x 100 range and testing between the source and drain of an N channel JFET: A. readings should be equal in both directions. B. with positive on anode, reading should be 1/100th that of the opposite polarity. C. with negative on anode, reading should be 1/100th that of the opposite polarity. D. this check provides no useful information.
A. readings should be equal in both directions.
Which wire size is physically largest? A. #8 B. #12 C. #16 D. #24
A. #8
If R = 200 ohms and I = .02 amps. What is the value of P (power)? A. .08 watts B. .8 watts C. 4 watts D. 8 watts
A. .08 watts
The average of a full sine wave rectified voltage is: A. .637 x Peak. B. .707 x Peak. C. .707 x Peak to Peak. D. 1.414 x Average
A. .637 x Peak.
The normal open circuit voltage for each nickel-cadmium cell is approximately: A. 1.2. B. 2.1. C. 3.4. D. 6.3.
A. 1.2.
Adding the binary numbers 101011 and 001110 will give you what result? A. 111001 B. 111111 C. 001010 D. 111011
A. 111001
Which wire gauge has the largest diameter? A. 20 B. 24 C. 28 D. 32
A. 20
Decimal 50 would appear as ____ in Hex. A. 32 B. 62 C. 101000 D. 110010
A. 32
The effective voltage of a 100V Peak-to-Peak sine wave is: A. 35.35 VAC. B. 70.70 VAC. C. 141.4 VAC. D. 31.8 VAC.
A. 35.35 VAC.
A capacitor (3/8" x 1/8" ceramic or mica) marked 47k is: A. 47pf+/-10%. B. 4.7 μf +/- 5%. C. 47 μf +/- 20%. D. 47 mf+/-10%.
A. 47pf+/-10%.
The gain of an op-amp is directly, but inversely, related to bandwidth as input frequency increases. A. Always B. Never C. Either can be changed without affecting the other. D. It can affect bandwidth but higher gain affects bandwidth so little that it is effectively insignificant
A. Always
Which is LEAST likely to cause ESD damage to a MOSFET? A. Flux B. Solder sucker C. Human finger D. Wick
A. Flux
The energy stored in a coil is measured in: A. Henrys. B. Joules. C. Farads. D. Volts.
A. Henrys.
" ______ " is a term describing many op-amp circuits. A. Inverting B. Bi-directional C. Low-Pass D. Open Quadrature
A. Inverting
Of these choices, the display of a DMM would probably be: A. LCD. B. Pointer. C. CRT. D. Floating bal
A. LCD.
In a typical electrical generator, a small DC voltage applied to the field windings is able to control the output level of the generator. A. True B. False
A. True
The rotor in an induction motor is not connected to AC or DC power. A. True B. False C. It depends on speed limitations. D. These have no rotor.
A. True
A fuse which has its fusible wire wrapped around an insulator is: A. a Slo-Blo type fuse. B. an Inductive fuse. C. a capacitive fuse. D. intended for high voltage use.
A. a Slo-Blo type fuse.
A pi filter is an inductor with: A. a capacitor at each end to common. B. a capacitor at each end in series. C. a resistor at each end to common. D. a resistor at each end in series.
A. a capacitor at each end to common.
0 dBm, when referring to audio signals means:decibels referenced to 1 milliwatt. A. decibels referenced to 1 milliwatt. B. decibels referenced to 1 millivolt pk-pk. C. decibels referenced to 1 volt pk-pk. D. zero signal output.
A. decibels referenced to 1 milliwatt.
Moving one plate of a capacitor further away from the other will: A. decrease capacitance. B. increase capacitance. C. decrease voltage rating. D. increase mutual transconductance.
A. decrease capacitance.
You would probably prefer a digital VOM over an ordinary analog meter: A. for most accuracy. B. to insure operator safety. C. for convenience. D. when the signals are intermittent.
A. for most accuracy.
FM utilizes _____ where AM utilizes signal level variations. A. frequency variations B. power variations C. sideband modulations D. phase modulations
A. frequency variations
A component that reduces in resistance as it is heated: A. is a negative temperature coefficient thermistor. B. is a positive temperature coefficient thermistor. C. is a varactor. D. is a thermocouple.
A. is a negative temperature coefficient thermistor.
The radio communication mode that utilizes the basic frequency and one of the side bands: A. is called "SSB." B. is FM. C. must be line-of-sight. D. utilizes CB technology.
A. is called "SSB."
Sideband frequencies are produced when an radio carrier frequency is: A. modulated. B. transmitted at minimum power level. C. fed to a splitter. D. radiated into space.
A. modulated.
A differential amplifier with two identical in-phase signals on the inputs will have an output ________. A. of zero B. twice the input, but same shape C. that cannot be determined with this information D. one half the input signal
A. of zero
Integrated Circuit failures often exhibit: A. open or short conditions. B. liquid material leakage. C. audible noise. D. power supply overloads.
A. open or short conditions.
A capacitor will charge to what percent of full charge in one RC time? A. .707 B. 33.3 C. 63.2 D. 67.6
C. 63.2
An LCD operates by polarizing the light through filters. The fluid rotates the light ______ degrees. A. 30 B. 45 C. 90 D. 180
C. 90
The fact than an inductor opposes any change in current is true of: A. AC signals only. B. DC signals only. C. AC and DC signals. D. UHF signals more than VHF.
C. AC and DC signals.
A printer directly connected to a personal computer would use a _____ connection. A. VGA B. Ethernet 100 Base-T C. USB or parallel Centronics D. DB15
C. USB or parallel Centronics
A dual trace oscilloscope differs from a single trace in that only the dual trace scope: A. has two cathode ray guns. B. has a Z input. C. alternates sweeps. D. has intensified traces.
C. alternates sweeps.
Standing waves on a transmission cable: A. indicate maximum power out. B. indicate less than optimum signal transmission, but should cause no concern. C. can be caused by poor termination. D. can be located with a reflectometer.
C. can be caused by poor termination.
Correctly connecting a properly rated zener diode across a power supply load will: A. protect the power transformer. B. increase the output DC. C. limit the output DC. D. eliminate ripple.
C. limit the output DC.
The power transformer in a power supply: A. always steps voltages up. B. always steps voltages down. C. might step voltages up or down. D. always steps current up.
C. might step voltages up or down.
A small power drill or electric mixer would probably be powered by a/an ______ motor. A. three-phase B. induction C. series D. parallel
C. series
Lead-free type solder for electronics work is made from: A. silver and bismuth. B. lead and tin. C. silver and tin. D. acid core.
C. silver and tin.
To test an SCR with an ohmmeter: A. this cannot be done. B. check resistance the same as transistors. C. with + to anode and - to cathode, short gate and anode together. Should go from near "open" to near "short." D. with - to anode and + to cathode, short gate and cathode together. Should go from near "open" to near "short."
C. with + to anode and - to cathode, short gate and anode together. Should go from near "open" to near "short."
Voltage is: A. potential difference between two points. B. amount of current flow. C. quantity of electronics moving in a conductor. D. opposition to resistance.
A. potential difference between two points.
A "Digital Storage Oscilloscope": A. uses micro processing and memory to allow close analysis of signals. B. is specially designed for analyzing digital signals. C. converts analog input signals to a digital display. D. converts digital input signals to an analog display.
A. uses micro processing and memory to allow close analysis of signals. B. is specially designed for analyzing digital signals. C. converts analog input signals to a digital display.
A capacitor opposes any change in: A. voltage. B. current. C. frequency. D. reactance.
A. voltage.
Applying positive voltage to the P end and negative to the N end of a germanium diode: A. will forward bias it. B. will reverse bias it. C. probably will damage it. D. should have no effect on it.
A. will forward bias it.
You should expect the video amplifier in a radar or TV receiver to have a frequency response of: A. 20 Hz -20 kHz. B. 20 kHz -180 kHz. C. 0-6 MHz. D. 88 MHz -108 MHz.
C. 0-6 MHz.
0 dBmV is what level of received TV signal? A. Zero B. .0001 Volt C. 1000 microvolts D. 1 Volt
C. 1000 microvolts
What decimal number is represented by the binary number 01101010 ? A. 6A B. 53 C. 106 D. 152
C. 106
A power supply which measures 50 volts when under a small load and 40 volts under a heavy load has what percent regulation using the % of regulation formula (% = (EnL - EfL) / EfL x 100)? A. 100 B. 50 C. 20 D. 0
C. 20
What is the total capacitance of three capacitors valued at 100μf, 100μf and 50μf when connected in a series? A. 25 μf B. 250 μf C. 25 pf D. 250 pf
C. 25 pf
An 8-bit binary code allows _____ logical combinations. A. 16 B. 64 C. 256 D. 512
C. 256
In a 3-input AND gate: A. 1 input must be high in order to have a high output. B. 2 inputs must be high for a high output. C. 3 input must be high for a high output. D. All three inputs must be high to have a low output.
C. 3 input must be high for a high output.
8.33 meters is the full wavelength in air for what RF frequency? A. 72 MHz B. 83.3 MHz C. 36 MHz D. 16.66 MHz
C. 36 MHz
