Description : A series mode crystal is marked 10.000 MHz., It is used in a circuit that operates the crystal in its parallel mode. The circuit can be expected to A) Run below 10 MHz B) Run at 10 MHz C) Run above 10 MHz D) Not oscillate.
Last Answer : C) Run above 10 MHz
Description : An oscillator that uses crystal control should be A) Frequency stable B) useful only at low frequencies C) AVFO D) none of the above.
Last Answer : A) Frequency stable
Description : Load regulation is a measure of a power supplies ability keep a constant output under conditions of changing A) Line voltage B) Current demand C) Temperature D) Oscillator frequency.
Last Answer : A) Line voltage
Description : The major function of transistor. Q2 is A) It provides voltage gain B) It provides the feedback signal C) It isolates the oscillator from loading effects D) It provides a phase shift.
Last Answer : ) It provides a phase shift.
Description : Which of the following is not true: A) An oscillator is a circuit that converts DC to AC B) An oscillator is an amplifier that supplies its own input signal C) All oscillators generate sine waves D) In phase feedback is called positive Feedback
Last Answer : C) All oscillators generate sine waves
Description : Which distortion is least objectionable in case of audio amplifers? A) Phase distortion B) Frequency distortion C) Harmonic distortion D) Inter modulation distortion.
Last Answer : A) Phase distortion
Description : The Bandwidth of an RC-coupled amplifier is limited by: A) coupling capacitors at the low frequency end and bypass capacitors at the high frequency end B) coupling capacitors at the high frequency ... at the low frequency end and bypass as well as coupling capacitors at the high frequency end.
Last Answer : C) bypass and coupling capacitors at the low frequency end and shunt capacitors at the high frequency end and
Description : The change in base current will be A) 0.66 micro ampere B) 6.6 micro amperes C) 66 micro amperes D) 660 micro amperes.
Last Answer : A) 0.66 micro ampere
Description : What is the electrical wavelength of a 500 MHz signal? A. 60 centimeters B. 6 meters C. 0.06 meter D. 60 meters
Last Answer : A. 60 centimeters
Description : In an amplifier if conductor during the cycle is from 0 to 90° and again from 180° to 270°, the amplifier will be termed as A) Class A B) Class B C) Class C D) Class AB.
Last Answer : B) Class B
Description : An ideal voltage amplifier should have A) Ri = 0, R0 = 0 B) Ri = 0, R0 =∞ C) Ri = ∞, R0 = 0 D) Ri = ∞, R0 = ∞.
Last Answer : C) Ri = ∞, R0 = 0
Description : Which of the following methods cannot be used to increase the bandwidth for cascaded RF amplifier stages? A) Wave traps in each stage B) Stagger tuning C) A shunt damping resistor across each tuned circuit D) Doubled tuned transformers with tighter coupling
Last Answer : A) Wave traps in each stage
Description : A push pull amplifier balances out A) Odd harmonics B) Even harmonics C) Both odd as well as even harmonics D) Neither odd nor even harmonics.
Last Answer : A) Odd harmonics
Description : Which amplifier will be preferred for highest gain? A) Darlington's pair B) Cascade amplifier C) Cascode amplifier D) Depends on the circuitry
Last Answer : C) Cascode amplifier
Description : Which of the following contributes to harmonics distortion in amplifiers? A) Positive feedback B) Presence of noise C) Defective active device D) Non linearity in active device.
Last Answer : D) Non linearity in active device.
Description : In an amplifier the collector voltage equals the full V+ of 28 V instead of the normal 12 V which of the following can be the trouble? A) RL is open B) Cc is open C) RE is open D) CE is shorted.
Last Answer : B) Cc is open
Description : In a resistance loaded amplifier, the gain decreases a high frequencies because A) Of decreasing reactance of the stray CT B) Increasing reactance of the stray CT C) Increasing reactance of CC D) Decreasing reactance of CC.
Last Answer : D) Decreasing reactance of CC.
Description : A IGFET is a A) Linear device B) Square law device C) Half power device D) 3/2 power law device.
Last Answer : B) Square law device
Description : An FET has a gate source bias of 2 V. The ac input signal is ± 1.2 V. The class of operation is A) A B) B C) C D) AB
Last Answer : D) AB
Description : In a resistance loaded, RC coupled amplifier the dc component is blocked by A) Load resistance RL B) Coupling capacitor, CC C) RB D) The transistor.
Last Answer : B) Coupling capacitor, CC
Description : If the operating point of an NPN transistor amplifier is selected in saturation region, it is likely to result in A) Thermal runaway of transistor B) Clipping of output in the positive half of the ... for high dc collector supply D) Clipping of output in the negative half of the input signal
Last Answer : B) Clipping of output in the positive half of the input signal
Description : Which of the following combinations has no phase inversion of the signal? A) Two CE stages B) CE and CC stages C) Three CE stages D) CE stage and emitter follower.
Last Answer : A) Two CE stages
Description : The Darlington pair consists of the following two stages A) CE and CC B) Both C) Both CC D) CE and CB
Last Answer : C) Both CC
Description : Which of the following circuit would be preferred for a 455 kHz IF amplifier? A) A resistance loaded B) Double tuned transformer C) Video amplifier D) Class C
Last Answer : B) Double tuned transformer
Description : Common base configuration is little used because A) It has low input impedance B) It has high input impedance C) It does not heat up D) It has very high gain.
Last Answer : A) It has low input impedance
Description : As compared to a CB amplifier, a CE amplifier has A) Lower current amplification B) Higher current amplification C) Higher input resistance. D) Both (B) & (C)
Last Answer : D) Both (B) & (C)
Description : Foldback current limiting has the advantage of A) Better pass transistor protection for long term overloads B) A defined turn on point C) Circuit simplicity D) All of the above.
Last Answer : A) Better pass transistor protection for long term overloads
Description : A crow bar is a power supply circuit that provides A) Conventional current limiting B) Foldback current. limiting C) Temperature control D) Voltage limiting.
Last Answer : D) Voltage limiting.
Description : Current limited power supplies can prevent damage to A) Rectifier diodes and power transformers. B) Pass transistors C) Other circuits in the system D) All of the above.
Last Answer : D) All of the above.
Description : In general, MOV devices are used to protect electronic equipment from dangerous operating conditions such as A) High temperatures B) Line transients C) Over current D) All of the above.
Description : What is the phase relationship of the signal at the collector of Q2 to the signal at the collector of Q, A) 0° B) 90° C) 180° D) 360°.
Last Answer : C) 180°
Description : What conditions are required for an amplifier to oscillate A) There must be feedback B) The feedback must be in phase C) The gain must be greater than the loss D) All the above are regd.
Last Answer : B) The feedback must be in phase
Description : The ideal characteristic of a voltage stablizer is A) constant output voltage with low internal resistance B) constant output current with low internal resistance C) constant output voltage with high internal resistance D) constant internal resistance with variable output voltage.
Last Answer : A) constant output voltage with low internal resistance
Description : Assume a frequency of 4 MHz, determine the phase shift offered by the line in the above problem. A. 108.5˚ B. 106.5˚ C. 115.5˚ D. 166.5˚
Last Answer : D. 166.5˚
Description : What is the local oscillator (mixer) frequency of the satellite with an uplink frequency in GHz band? A. 3500 MHz B. 4500 MHz C. 2225 MHz D. 2555 MHz
Last Answer : C. 2225 MHz
Description : An FM receiver whose intermediate frequency is 10.7 MHz, is experiencing image channel interference from a station transmitting on 121.1 MHz. If the local oscillator is tracking above, the receiver is tuned to A. 131.8 MHz B. 110.4 MHz C. 142.5 MHz D. 99.7 MHz
Last Answer : D. 99.7 MHz
Description : Refer to the deviation of the operating frequency of a crystal oscillator from its nominal value due to temperature variations. A. Drift B. Flash over C. Frequency deviation D. Deviation ratio
Last Answer : A. Drift
Description : In a radio transmitter, the frequency of the crystal oscillator will be stable for a long time if the quality factor of the crystal resonator is (a) > 100 (b) > 500 (c) > 1000 (d) > 20000
Last Answer : In a radio transmitter, the frequency of the crystal oscillator will be stable for a long time if the quality factor of the crystal resonator is > 1000
Last Answer : The crystal oscillator frequency is very stable due to High Q of the crystal.
Description : One of the following is a possible cause for a slow drift of frequency in a self-exited transmitter oscillator circuits resulting to a poor frequency stability. A. Loose shielding B. ... capacitor in the oscillator C. Poor soldered connections D. Faulty capacitor, resistor, tubes or resistors
Last Answer : B. Heating of capacitor in the oscillator
Description : One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency opereation and RF amplifier stage orstages that develop the ... to develop a good frequency stability. A. Goldsmith B. MOPA C. Alexanderson D. Hartley
Last Answer : B. MOPA
Description : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.
Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.
Description : Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections ... , or antenna circuits D. DC and RF heating of resistors, causing then to change values.
Last Answer : D. DC and RF heating of resistors, causing then to change values.
Description : The frequency stability of the oscillator output is maximum in _____. (a) Crystal oscillator (b) Phase shift oscillator (c) LC oscillator (d) Wien bridge oscillator
Last Answer : The frequency stability of the oscillator output is maximum in Crystal oscillator.
Description : What is the required quality factor for an SSB filter with the following data: center frequency= 1 MHz, the desired attenuation level of the unwanted sideband= 80 dB and the separation between sidebands= 200 Hz? A. 1,250 B. 12,500 C. 125,000 D. 25,000
Last Answer : C. 125,000
Description : What is the frequency of a 2-cm sound wave in sea water at 25˚C? A. 76 kHz B. 76 Hz C. 76 MHz D. 76 mHz
Last Answer : A. 76 kHz
Description : Which of the following precautions should be taken when troubleshooting various power circuits using a common solenoid-type mechanical voltage tester (wiggins)? A. Never use this tester on circuits greater ... voltage expected in the circuit in order to prevent damage from an off-scale reading.
Last Answer : Answer: A
Description : Which of the following characteristics is not typical of ionically bonded crystals? (a) Has no sharp melting point (b) Cleave into definite cleavage planes (c) Conducts when melted (d) Shatters when crystal is distorted
Last Answer : Ans:(a)
Description : Pick out the wrong statement. (A) Swenson-Walker crystalliser is a batch crystalliser (B) Super saturation of the solution is the driving potential for a crystal growth (C) The ... a solution is called mother liquor (D) The first stage of crystal formation is called nucleation
Last Answer : (A) Swenson-Walker crystalliser is a batch crystalliser
Description : If the crystal is moistened with water which colour of crystals appear---- (a) Green (b) Red (c) Blue (d) Yellow
Last Answer : (c) Blue