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CET study guide questions with complete solutions, Exams of Electronics

8.33 meters is the full wavelength in air for what RF frequency? ✔✔36 MHz Decimal 164 would appear as what in binary? ✔✔10100100 A resistor has color stripes yellow, violet, violet, silver. It is? ✔✔470 MegOhm +/- 10% What is the total capacitance of three capacitors valued at 100uf, 100uf and 50uf when connected in series? ✔✔25 pf What is the ripple frequency of a full wave single phase bridge rectifier operated at 60 Hz? ✔✔120 Hz What emits a voltage when heated or cooled? ✔✔Thermocouple

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CET study guide questions with

complete solutions

8.33 meters is the full wavelength in air for what RF frequency? ✔✔36 MHz

Decimal 164 would appear as what in binary? ✔✔ 10100100

A resistor has color stripes yellow, violet, violet, silver. It is? ✔✔470 MegOhm +/- 10%

What is the total capacitance of three capacitors valued at 100uf, 100uf and 50uf when connected in series? ✔✔25 pf

What is the ripple frequency of a full wave single phase bridge rectifier operated at 60 Hz? ✔✔120 Hz

What emits a voltage when heated or cooled? ✔✔Thermocouple

Adding the binary numbers 101011 and 001110 will give you what result? ✔✔ 111001

A component that reduces in resistance as it is heated. ✔✔A negative temperature coefficient thermistor

An autotransformer ✔✔has a single winding

A dual trace oscilloscope differs from a single trace in that only the dual trace scope: ✔✔alternates sweeps

If an RF signal Voltage is reduced by 6db it is then : ✔✔half the original size

Applying positive voltage to the P end and negative to the N end of a germanium diode: ✔✔will forward bias it

You would probably prefer a digital VOM over an ordinary analog meter: ✔✔for most accuracy

You should expect the video amplifier in a radar or TV receiver to have a frequency response of: ✔✔0-6 MHzd

The radio communication mode that utilizes the basic frequency and one of the side bands: ✔✔is called "SSB"

When using fiber optic to transfer a signal, the light must: ✔✔enter the "cone of acceptance"

The energy stored in a coil is measured in: ✔✔Henrys

The telephone communication term "Cellular" refers to: ✔✔small geographic areas covered by each base station

Integrated circuit failures often exhibit: ✔✔open or short conditions

Which of these would you normally choose to cause an LED to light? ✔✔3 VDC

A capacitor (3/8"x1/8" ceramic or mica) marked 47K is: ✔✔47 pf +/- 10%

A "digital storage oscilloscope": ✔✔uses micro processing and memory to allow close analysis of signal.

Carbon microphones are much like variable: ✔✔resistors

An antenna that is longer than another: ✔✔will have a lower resonant frequency

An 8 bit binary code allows how many logical combinations. ✔✔ 256

An inductor in an electronic circuit: ✔✔resists AC current flow

A printer directly connected to a personal computer would use what kind of connection? ✔✔usb or parallel centronics

The digital method of representing characters by using combinations of zeros and ones is called: ✔✔Binary

AM utilizes signal level variations where FM utilizes : ✔✔Frequency variations

What decimal number is represented by the binary number 01101010? ✔✔ 106

Decimal 50 would appear as what number in Hex? ✔✔ 32

The display of a DMM would probably be: ✔✔LCD

A disadvantage of LCD is: ✔✔Environmental temperature sensitivity

A series DC motor with no load: ✔✔maybe damaged by excessive speed

Which motor maintains a constant speed with changing load? ✔✔Shunt

A small power drill or electric mixer would probably be powered by a ✔✔Series Motor

0 db when referring to audio signals means: ✔✔decibels referenced to 1 milliwatt

If a class A differential amplifier is using only one of its two possible inputs, what will the output shape be? ✔✔Exactly the same as the one input

Voltage is: ✔✔Potential difference between two points

What is a term describing many op-amp circuits? ✔✔inverting

The gain of an op-amp is directly, but inversely, related to bandwidth as input frequency increases: ✔✔Always

The audio detector circuit in an AM radio most commonly is a: ✔✔diode

A differential amplifier with two identical in-phase signals on the inputs will have an output of: ✔✔zero

A fuse which has its fusible wire wrapped around an insulator is: ✔✔Slo-blo type fuse

The power transformer in a power supply: ✔✔Might step voltages up or down

Which of the below would be considered "basic" components of a non switching power supply? ✔✔Filter, regulator, rectifier, transformer

The average of a full sine wave rectified voltage is : ✔✔.637 X Peak

The ripple frequency for a half wave rectifier operating from 60 Hz electrical power is: ✔✔ 60 HZ

The effective voltage of a 100v Peak-to-peak sine wave is: ✔✔35.35 VAC

A pi filter is an inductor with: ✔✔A capacitor at each end to common

An inductor opposes any change in: ✔✔current

A capacitor opposes any change in: ✔✔voltage

A capacitor will charge to what percent of full charge in one RC time? ✔✔63.

Moving one plate of a capacitor further away from the other will: ✔✔decrease capacitance

The fact that an inductor opposes any change in current is true of: ✔✔AC and DC signals

If you increase the value of a capacitor, the capacitive reactance will: ✔✔decrease

In checking a capacitor to see if it is really shorted, open or leaky: ✔✔you would use the highest ohm meter range.

The capacitor in a power supply capacitive filter: ✔✔Is in parallel with the load

The time required to discharge a capacitor depends on the: ✔✔combination of LRC across its terminals.

With a given filter type, pure filtering is easiest with: ✔✔High frequencies

A power supply whose output voltage does not change whether the load is light or heavy would have what percent of regulation? ✔✔ 0

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)/EfLX100)? ✔✔ 20

Correctly connecting a properly rated zener diode across a power supply load will: ✔✔limit the output DC

A triac in a power control circuit: ✔✔acts as an on/off switch

What specification should not be of concern regarding wire conductors? ✔✔capacitance

The normal open circuit voltage for each nickel-cadmium cell is approximately? ✔✔1.2 volts

Lead free type solder for electronics work is made from: ✔✔Silver and Tin

Soldering stations used for electronics circuit-board work have historically been(approximately): ✔✔30 Watts

Solder flux mainly: ✔✔removes oxides on metals to be soldered

Laminations used for the core of a transformer: ✔✔must be insulated from each other

I=1 amp, R=10,000 ohms. What is the value of the voltage? ✔✔10,000 volts

If R=200 ohms and I=.02 amps. What is the value of P(power)? ✔✔.08 watts

Which frequency will have a higher loss when using coaxial cable transmission line? ✔✔1 Ghz

What is a reference antenna that all other antennas with gain are compared to? ✔✔dipole

A high frequency antenna is than a low frequency one. ✔✔is shorter

Standing waves on a transmission cable: ✔✔can be caused by poor termination

Sideband frequencies are produced when an radio carrier frequency is: ✔✔modulated

Doubling the power in a transmitter output is a: ✔✔3 db gain

0 db is what level of received TV signal? ✔✔1000 microVolts

A byte is: ✔✔8 bits

In a 3 input AND gate: ✔✔3 input must be high for a high output

An LCD operates by polarizing the light through filters. The fluid rotates the light: ✔✔ 90 degrees

To test an SCR with an ohmmeter. ✔✔with + to anode and - to cathode, short gate and anode together

Using the Rx100 range and testing between the source and drain of an N channel JFET: ✔✔readings should be equal in both directions

With + voltage to drain or source and a - voltage to the gate on an N channel JFET, internal resistance of the JFET will be: ✔✔High

Which is least likely to cause ESD damage to MOSFET ✔✔flux

A logic probe: ✔✔indicates high and low voltage conditions

In a typical electrical generator a small DC voltage applied to the field windings: ✔✔is able to control the output level of the generator

When working with and testing lead acid batteries ✔✔Always wear eye protection and never cause a spark

Audio signals, such as the output from DVD players, satellite receivers and preamplifers, usually are of what amplitude for input to a TV, modulator or other equipment? ✔✔1 voltage peak to peak

Which of these signal parameters does a spectrum analyzer show? ✔✔Magnitude and frequency

Permanent, non-volatile, non removable data storage in a computer is: ✔✔ROM

What should be used first to clean a corroded plated soldering iron tip? ✔✔flux, cloth and heating

When soldering high voltage connections: ✔✔Leave the terminal with a smooth and rounded covering of solder

Class AB operation of an audio amplifier means that current flows through the active device(tube, transistor,FET,IC) for how many degrees of the input signal wave? ✔✔more than 180 but less then 360

A track on a computer disk is: ✔✔divided into sectors

A PC has conventional RAM and ROM memory area(in a PC it is 0 to 640 kilobytes); upper memory area(640 kilobytes to 1 meg) and extended memory area(above 1 meg). What other names for internal memory types do PCs have? ✔✔Tape Drive

Which video system has the highest resolution? ✔✔XVGA

You would want to use a dual trace oscilloscope to measure: ✔✔signal difference between two points

Common Intermediate Frequencies(IF's) and FM commercial broadcast receivers are: ✔✔ 455 MHz and 10.7MHz

Analog radio receiver signal compression: ✔✔reduces the high frequency received signal amplitude

Coaxial cable line losses at RF frequencies are due to: ✔✔wire resistance, capacitive and inductive reactance

You are troubleshooting audio reproduction equipment and measure the signal to be input into the audio amplifier. What approximate RMS level would you expect the signal to be? ✔✔ 1000 millivolts

The noise level in a radio receiver is generated mostly in the: ✔✔RF section

The fast charging rate for a NiCad of Ni-Mh battery should not exceed: ✔✔10% of its AHr or ampere hour rating

Which of the following in a PC would be part of disk operations? ✔✔SATA or IDE controller

An LED ✔✔can be used as a fiber optic signal source

A dual trace oscilloscope may have ✔✔A Z input for intensity modulation

The gain of an op-amp connected as an inverting amplifier is determined by the external ✔✔feedback and input resistors

Which propagation condition would be significant for a UHF signal to be received at a distance of 500 miles? ✔✔Tropospheric ducting

A three input NAND has two low inputs and one high input. The output is: ✔✔High

Which of these would be considered a component of a "basic" power supply? ✔✔diode rectifier

A "Video Signal" is defined as: ✔✔baseband including visual information

You are servicing a power supply and have disconnected power. It has several 250 uf capacitors connected in parallel. To avoid shock these capacitors: ✔✔Should be discharged to chassis ground, through a suitable resistor

A schematic used in electronic: ✔✔is much like a road map for following signals

High voltage should be discharged before servicing a product. After disabling AC input power, discharge a high voltage power source by: ✔✔draining thru a large value resistor to chassis ground

Which of these would be an important electrical consideration in the use of a transformer? ✔✔The operating frequency

If a 12v product is dissipating 50w, how much load resistance does the device represent? ✔✔2. ohms

An "audio signal" is defined as: ✔✔frequencies in the 20Hz to 15000Hz range

What will cause a generator to produce DC voltage rather then AC? ✔✔the commutator

You suspect the unit has an internal short. To prevent further damage when you apply power, you should: ✔✔insert a low resistance high wattage(100ohm, 10w) resistor in series with the power input.

A ripple counter: ✔✔Is two or more logical flip-flops connected sequentially with the input pulses toggling the first one

When voltage is applied to a capacitor: ✔✔current is maximum at first, then reduces as the capacitor becomes charges.

An electrolytic capacitor in series between the power transformer and the rectifiers in a power supply: ✔✔is part of a voltage doubler circuit

Information travels through optic fiber via the flow of: ✔✔photons

You would most likely prefer an analog VOM over a DMM for: ✔✔accuracy

Which of these circuits would most likely use a zener diode? ✔✔a power regulator

A block in a digital diagram is called a NOR. Which is true? ✔✔It is a NOT OR or Inverted OR

Which of these statements is most true relating to schematic diagrams of electronic devices? ✔✔They represent signal paths

In personal computer technology, ROM indicates: ✔✔memory that may only be read from

A light emitting diode will light when: ✔✔It is forward biased.

A zener diode is rated 6.3V. This tells you: ✔✔it conducts to limit the voltage across it to 6.3V

A triac is frequently used: ✔✔for motor speed control, to electronically turn equipment on and off

A technician must be knowledgeable about "ESD": ✔✔because static discharge can destroy many components.

In a motor, the counter-emf voltage induced in the armature the source current. ✔✔subtracts from

One significant difference between a TV antenna and a CB antenna would be: ✔✔TV is polarized horizontal while CB is vertical

"Switching power supplies": ✔✔sometimes called DC to DC converters, maybe operated of AC or DC sources

Which of these would you likely find in a DC motor speed control circuit? ✔✔An op-amp

A transformer on a schematic has two leads connected to the primary and three to the secondary, one to each end and one in the middle. This is an: ✔✔center tapped secondary transformer

The 9 pin DB9 connector serial port on a PC is commonly called the: ✔✔RS232 standard

Three capacitors, of 470pf, 560pf and .47pf are in parallel with each other. The total is: ✔✔1030.47pf

Ohm's law provides equations relating to: ✔✔Volts, amps and resistance

A power source such as a generator or battery might be compared to what component in a water supply system? ✔✔A water tank

Which of these is a good indication of the quality of an analog meter? ✔✔The ohms per volt rating

The vertical axis of an oscilloscope display is also called the: ✔✔Y axis

If you increase the value of an inductor, the inductive reactance will: ✔✔increase

Which would least likely be a high-voltage(above 1000V) capacitor? ✔✔electrolytic

The rechargeable cell currently used in many consumer portable products would be: ✔✔Lithium-ion

A solid-state regulator: ✔✔Varies conduction to maintain a level output voltage

A current-carrying conductor is placed in a magnetic field perpendicular to the lines of flux. It tends to move in what direction to the force of magnetic lines of flux, as determined by Flemings left-hand rule. ✔✔an opposite

The antenna used to compare the gain of other antennas is called a: ✔✔dipole

The component that effectively becomes a short when turned on, and is turned off by disconnecting the path from the anode to cathode is the: ✔✔silicon controlled rectifier

Which of these terms would you most expect to see when referring to types of resistors? ✔✔metal film

"microwave" as used in radio electronics, refers to: ✔✔1 GHz - 100 GHz radio frequencies

A differential amplifier whose two input signals are equal, but 180 degrees out of phase, will have an ✔✔maximum output signal

Which of these can be used to control the output level of a generator? ✔✔small DC voltage applied to the field winding

Impedance(Z, in ohms) includes: ✔✔Resistance, capacitive reactance and inductive reactance

The velocity factor in an RF transmission line is determined by: ✔✔the dielectric material between the center conductor and shield

A fuse, marked 250V, 650 ma can be used in circuits with an "open-fuse" supply voltage of: ✔✔125 volts

A thermistor: ✔✔changes resistance with temperature

When a transformer is designed, what most determines the output voltage from the secondary? ✔✔The ratio of primary to secondary turns

Adding armature windings in parallel to a generator's existing windings: ✔✔improves its voltage stability

A 10W signal is received at 5W. How many dB loss? ✔✔3 dB loss

It is desired to raise the power to a speaker from 15W to 30. This is a: ✔✔3dB increase

Which of these IC or semiconductor devices normally requires the most careful handling to avoid damage by static electricity? ✔✔CMOS

Which of these components most closely compares to the output of a solar cell? ✔✔A NiCad battery

Three series inductors have values of 20mh, 30mh and 40mh respectively total inductance is: ✔✔90mh

Phototransistors: ✔✔can be sensitive to invisible light

To simplify the following of an electrical signal path through circuitry you could: ✔✔use a block diagram

AC power outlet strips with surge suppressors will include at least one: ✔✔MOV

Connecting 3 capacitors of .05uf, 20uf and 40uf in series results in a total capacitance of: ✔✔.0498uf

You would use the formula(Lt = L1+L2+L3): ✔✔To find the total inductance in a series circuit

The fifth color band on a 5% resistor is yellow. This tells you: ✔✔its failure rate

VHF or UHF antennas don't use waveguides as feed lines because: ✔✔the large dimensions at these wavelengths make other trans lines more practical.

To trace a logic path, you might use: ✔✔A logic pulser

Ordinary alpha numeric information transmitted by a computer is converted to binary using: ✔✔an encoder

In electronic devices what term refers to residual magnetism? ✔✔Hysteresis

Some variable capacitors are made so the plates interleave. The capacitance varies as the plates open(separate) and close. As they open: ✔✔The capacitance decreases

In VOM's voltage multiplier resistors are important: ✔✔in the voltage scales

In a series tuned circuit, to increase the resonant frequency, you would need to: ✔✔decrease the inductance

A mosfet: ✔✔amplifies signal voltage variations

Torroid cones are used in transformers for: ✔✔concentrating the magnetic lines of flux