Description : A tube has a transconductance of 800 mhos and a load resistor of 50 kohms. When control grid voltage varies by 6 volts, the plate voltage will vary by what amount?
Last Answer : 240 volts.
Description : If the mu of a tube is 85 and the signal at the control grid is 4 volts ac, the plate voltage will vary by what amount?
Last Answer : 340 volts.
Description : The plate voltage of a tube will vary 126 volts when a 3-volt ac signal is applied to the control grid. What is the gain of this tube?
Last Answer : 42.
Description : What effect does transit time have on a conventional triode operated at uhf frequencies?
Last Answer : It causes the control grid to short to the cathode
Description : What effect does the shielding of the screen grid by the control grid have on plate current in beam-forming tetrodes?
Last Answer : By increasing the number of electrons that reach the plate, plate current is increased.
Description : Why does the grid have a greater effect than the plate on electron flo
Last Answer : Because it is closer to the cathode.
Description : Which of the following types of noise becomes of great importance at frequencies? A. Shot noise B. Random noise C. Impulse noise D. Transit-time noise
Last Answer : D. Transit-time noise
Description : How does fog affect radio waves at frequencies above 2 gigahertz?
Last Answer : It can cause attenuation by absorbtion.
Description : What is the filter called in which the low frequencies do not produce a useful voltage?
Last Answer : High-pass filter, low-frequency discriminator, or low-frequency attenuator.
Description : Trade-offs between competing effects are necessary for high speed response. Which competing effect (fast transit time, low capacitance, or high quantum efficiency) requires a thin active area?
Last Answer : Fast transit time.
Description : What type filter is used to block the passage of current for a narrow band of frequencies, while allowing current to flow at all frequencies above or below this band?
Last Answer : . Band-reject.
Description : What is the device called that will separate alternating current from direct current, or that will separate alternating current of one frequency from other alternating currents of different frequencies?
Last Answer : A filter.
Description : What is the band of frequencies called that is included between the two points at which current falls to 70 percent of its maximum value in a resonant circuit?
Last Answer : Bandwidth of the circuit
Description : What is the relationship of current to voltage in a circuit?
Last Answer : current increases as voltage increases.
Description : What is the phase relationship between current and voltage in an inductor?
Last Answer : Current lags voltage by 90° (ELI).
Description : The main plate of a transit is divided into 1080 equal divisions. 60 divisions of the Vernier coincide exactly with 59 divisions of the main plate. The transit can read angles accurate upto (A) 5" (B) 10" (C) 15" (D) 20"
Last Answer : (D) 20"
Description : How do uhf tubes counter the effects of transit time?
Last Answer : By reducing the spacing between tube elements.
Description : What causes dc bias energy to be absorbed by avalanche electrons and given up to the microwave field applied to an avalanche transit-time diode?
Last Answer : The negative-resistance property.
Description : What is the junction arrangement of the original avalanche transit-time diode?
Last Answer : Pnin.
Description : What characteristic of a gunn oscillator is inversely proportional to the transit time of the domain across the semiconductor?
Last Answer : The frequency.
Description : A large negative voltage is applied to the plate of a diode, and a largewhat tube parameter has been exceeded?
Last Answer : Peak Inverse Voltage (PIV).
Description : What type of insulator works well at very high frequencies?
Last Answer : A shorted quarter-wave section called a metallic insulator.
Description : At very high frequencies, what characteristics are displayed by ordinary insulators?
Last Answer : The characteristics of the dielectric of a capacitor.
Description : What is the filter called that passes low frequencies but rejects or attenuates high frequencies?
Last Answer : Low-pass filter, high-frequency discriminator or high-frequency attenuator.
Description : What is an advantage of using horizontal polarization at high frequencies?
Last Answer : Less interference is experienced by man-made noise sources
Description : What type of coupling is most effective at high frequencies?
Last Answer : Impedance coupling.
Description : Which of the listed components does line 'C' represent for the transistor illustrated? EL-0068 A. Grid B. Plate C. Emitter D. Collector
Last Answer : Answer: C
Description : What are the three elements of a bipolar transistor? Are they the: w) grid, plate, cathode x) suppressor, deflector, target y) energizer, controller, terminus z) emitter, base, collector
Last Answer : ANSWER: Z -- EMITTER, BASE, COLLECTOR
Description : Once ionization has occurred in a thyratron, what control does the control grid have over the tube’s operation?
Last Answer : None.
Description : What is the major difference in grid construction between power pentodes and conventional pentodes?
Last Answer : Conventional pentodes have a staggered grid arrangement, while power pentodes have a shielded grid arrangement.
Description : What serves as a grid in a magnetron?
Last Answer : A magnetic field.
Description : In a circuit using grid-leak biasing, the coupling capacitor (Cc) chargcharge path?
Last Answer : rkg, the cathode to grid resistance.
Description : Why the control grid of a triode amplifier is negatively biased?
Last Answer : To prevent them from drawing grid current.
Description : The suppressor grid is added to a tetrode to reduce what undesirable characteristic of tetrode operation?
Last Answer : Secondary emission.
Description : What undesirable effect does the screen grid in a tetrode create?
Last Answer : Secondary emission, and noise.
Description : How does the addition of a screen grid in a tetrode reduce interelectrode capacitance?
Last Answer : The interelectrode capacitance (cpg) is divided between two series capacitances; thus, cpg is greatly reduced.
Description : When is a control-grid modulator used?
Last Answer : In cases when the use of a minimum of af modulator power is desired.
Description : kilohertz (kHz) is a unit which measures? A. Power used by a current of one ampere B. Electromagnetic radio wave frequencies (Answer) C. Voltage D. Electric resistance
Last Answer : B. Electromagnetic radio wave frequencies (Answer)
Description : Give the desired relationship between fundamental axes of transit theodolite.
Last Answer : The desired relationships between fundamental axes of transit theodolite when in perfect adjustment are : 1) The axis of plate level must be perpendicular to the vertical axis. 2) The line of ... If the instrument has fixed vernier for vertical circle, it must read zero in levelled position.
Description : . Why are coaxial lines more efficient at microwave frequencies than two-wire transmission lines?
Last Answer : The electromagnetic fields are completely confined
Description : A cavity that vibrates at its natural frequency produces a louder sound than at other frequencies. What term is used to describe this phenomenon?
Last Answer : Resonance.
Description : What type filter is used to allow a narrow band of frequencies to pass through a circuit and attenuate all other frequencies above or below the desired band?
Last Answer : Bandpass.
Description : What term is used to describe the frequency at which the filter circuit changes from the point of rejecting the unwanted frequencies to the point of passing the desired frequencies?
Last Answer : Frequency cutoff (fco).
Description : When a wide band of frequencies is transmitted simultaneously, each frequency will vary in the amount of fading. What is this variable fading called?
Last Answer : Selective fading.
Description : Receiver bandwidth is defined as those frequencies spread between what two points of the receiver response curve?
Last Answer : Half-power points.
Description : What IF frequencies are normally used in radar receivers
Last Answer : Thirty or sixty megahertz.
Description : What transmitter component allows the radiation of a large number of discrete frequencies over a wide band?
Last Answer : . Frequency synthesizer.
Description : Why do 2D air-search radars use relatively low carrier frequencies and low pulse-repetition rates?
Last Answer : Increased maximum range.
Description : Is it possible for a transmission line to operate improperly at certain frequencies and properly at others?
Last Answer : Yes, it is quite common.
Description : What device sweeps a band of frequencies to determine frequencies and amplitudes of each frequency component?
Last Answer : Spectrum analyzer.