Description : What starts the oscillations in a negative-resistance magnetron?
Last Answer : The application of the proper magnetic field.
Description : What is the typical frequency range about the center frequency of a tunable magnetron?
Last Answer : . ±5 percent.
Description : What is the effect on magnetron operation if the magnetic field strength is too high?
Last Answer : The magnetron will not oscillate.
Description : What is the frequency range of magnetron oscillators?
Last Answer : 600-30,000 megahertz.
Last Answer : ±5 percent.
Last Answer : . 600-30,000 megahertz.
Description : Name the procedure used to reduce excessive arcing in a magnetron?
Last Answer : Baking in.
Description : Capacitive tuning by inserting a ring into the cavity slot of a magnetron is accomplished by what type of tuning mechanism?
Last Answer : . A cookie-cutter tuner
Description : Magnetron tuning by altering the surface-to-volume ratio of the hole portion of a hole-and-slot cavity is what type of tuning?
Last Answer : Inductive.
Description : Why is the pi mode the most commonly used magnetron mode of operation
Last Answer : Greater power output.
Description : What are the electrons called that give up energy to the ac field in a magnetron?
Last Answer : Working electrons.
Description : What is the primary difference in construction between the basic magnetron and the negativeresistance magnetron?
Last Answer : The negative-resistance magnetron has a split plate
Description : A magnetron will produce oscillations when the electrons follow what type of path?
Last Answer : Circular.
Description : What element in the magnetron causes the curved path of electron flow?
Last Answer : The permanent magnet.
Description : What controls the output frequency of a magnetron?
Last Answer : . The resonant cavities.
Description : A cylindrical copper block with resonant cavities around the circumference is used as what component of a magnetron?
Last Answer : Anode or plate
Description : What serves as a grid in a magnetron?
Last Answer : A magnetic field.
Description : What is the term used to identify the amount of field strength required to cause the electrons to just miss the plate and return to the filament in a circular orbit?
Last Answer : The critical value of field strength
Description : If a three-phase induction motor is operated under a light load and it develops an open in one of its supply lines, the motor will _____________. A. continue to run, but will vibrate and have reduced ... speed up due to the reduced number of poles C. run cooler due to reduced current flow D. stop
Last Answer : Answer: A
Description : 55 When a 400Hz transformer is operated at 50Hz its KVA rating is A. Reduced to 1/8 B. Increased 8 times C. Unaffected D. Increased 64 times
Last Answer : A. Reduced to 1/8
Description : If an insulating material is operated beyond the maximum allowable temperature, its life is (a) drastically increased (b) drastically reduced (c) unaffected (d) none of the above
Last Answer : (b) drastically reduced
Description : If a voltage (positive or negative) is measured on the "1" output of a flip-flop, what state is it in?
Last Answer : SET state.
Description : What would be the output of a negative clamper with a bias potential of −5 volts and an input voltage swing from +50 to −50 volts?
Last Answer : -5 volts.
Description : . In a common anode, seven-segment LED display, an individual LED will light if a negative voltage is applied to what element?
Last Answer : The cathode.
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 : If the load requirement consists of both positive and negative voltages, what technique is used in the voltage divider to supply the loads from a single voltage source?
Last Answer : The ground (reference point) is placed in the proper point in the voltage divider so that positive and negative voltages are supplied
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 : At what portion of the magnetization curve should a magnetic amplifier be operated?
Last Answer : . The knee of the curve.
Description : What must the physical length of a transmission line be if it will be operated at 15,000,000 Hz?
Last Answer : . λ = 20 meters
Description : The point on the current curve of a gallium-arsenide semiconductor at which it begins to exhibit negative resistance is called what?
Last Answer : Threshold.
Description : What causes the negative-resistance property of tunnel diodes?
Last Answer : The tunneling action
Description : Will the filament resistance of a bulb be higher at normal temperature or in incandescent condition ?
Last Answer : As the resistance increases with increasing temperature, the resistance of the filament of the bulb will be higher than the normal temperature.
Description : A filament bulb `(500 W, 100 V)` is to be used in a `230 V` main supply. When a resistance `R` is connected in series, it works perfectly and the bulb
Last Answer : A filament bulb `(500 W, 100 V)` is to be used in a `230 V` main supply. When a resistance `R` is ... Omega` B. `46 Omega` C. `26Omega` D. `13 Omega`
Description : What happens to the resistance of a filament if it is replaced by a shorter wire?
Last Answer : the resistance decreasesAPEX
Description : Consider the following statements: 1. when an electric bulb is switched on, the resistance of its tungsten filament increases. 2. the resistance of pure metals increases on heating. Which of the above statements is/are correct? (a) Both 1 and 2 (b) only 1 (c) only 2 (d) Neither 1 nor 2
Last Answer : Ans:(a)
Description : The filament of an electric lamp becomes white hot but the lead-in wires holding the filament are only slightly heated because they (a) have smaller current passing through them (b) have very low resistance (c) have higher melting point (d) are made of black iron
Last Answer : Ans:(b)
Description : Is the filament resistance lower or higher in a 500 watt light bulb than in a 100 watt light? Assume that both bulbs have been designed to operate at 110 volts.
Last Answer : ANSWER: LOWER
Description : The hot resistance of a bulb’s filament is higher than its cold resistance because the temperature coefficient of the filament is:
Last Answer : positive
Description : The hot resistance of the bulb's filament is higher than its cold resistance because the temperature co-efficient of the filament is?
Last Answer : This is because resistance of a conductor increases with increase in temperature .
Description : The wiring diagram for the motor starting circuit shown in the illustration indicates ______________. EL-0007 A. resistance starting B. reduced voltage starting C. low voltage protection D. low voltage release
Last Answer : Answer: C
Description : Damp armature windings in a D.C. motor may lead to ____________. A. reduced voltage B. reduced current C. increased resistance D. overheating
Last Answer : Answer: D
Description : An across-the-line starter is typically used for which of the following applications? A. Reduced-current starting of large motors B. Low torque starting of small motors C. Low resistance starting of DC motors D. Full-voltage starting of motors
Description : A shunt-type voltage regulator is connected in serial/parallel (which one) with the load resistance.
Last Answer : In parallel.
Description : When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease (which one) in the resistance of the regulating device.
Last Answer : An increase.
Description : A shunt type voltage regulator is connected in series/parallel with the load resistance.
Last Answer : Parallel
Description : When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease in the resistance of the regulating device.
Last Answer : Increase.
Description : A series circuit consisting of three resistors has a current of 3 amps. If R1 = 20 ohms, R2= 60 ohms, and R 3 = 80 ohms, what is the (a) total resistance and (b) source voltage of the circuit?
Last Answer : (a) 160 ohms. (b) 480 ohms
Description : How is a multimeter changed from a voltage measuring device to a resistance measuring device?
Last Answer : By changing the position of the function switch
Description : A circuit is to be designed in which a capacitor must charge to 40 percent of the maximum charging voltage in 200 microseconds. The resistor to be used has a resistance of 40,000 ohms. What size capacitor must be used?
Last Answer : 0.1 microfarads 40% from the graph = 0.5