Description : Vacuum tubes have been replaced by-----? A. Conductors B. Diodes C. Transistors (Answer) D. None of these
Last Answer : C. Transistors (Answer)
Description : Which of the following statements comparing transistors and vacuum tubes is correct? A. Both transistors and vacuum tubes have a cathode that must be heated to give off electrons. B. A vacuum tube must ... flow. D. The anode of both transistors and vacuum tubes must be heated to give off electrons.
Last Answer : Answer: B
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 : Silicon diodes designed for a specific reverse breakdown voltage, become useful as an electronic power supply voltage regulator, called _____________. A. tunnel diodes B. hot-carrier diodes C. compensating diodes D. Zener diodes
Last Answer : Answer: D
Description : High vacuum diodes, gas-filled diodes, and germanium semiconductor diodes may all be used as _____________. A. potentiometers B. rectifiers C. power sources D. photocells
Description : Which of the devices listed is indicated by the symbols lettered 'A' to 'F', shown in the illustration? EL-0016 A. Diodes B. Linear inductors C. Capacitors D. Transistors
Last Answer : Answer: A
Description : Which electronic component was made out of semiconductor material? A) Vacuum tubes B) Transistors C) ICs D) All of above
Last Answer : Answer : C
Description : The main electronic component used in first generation computers was A) Transistors B) Vacuum Tubes and Valves C) Integrated Circuits D) None of above
Last Answer : Answer : B
Description : Chief component of first generation computer was A) Transistors B) Vacuum Tubes and Valves C) Integrated Circuits D) None of above
Description : Chief component of first generation computer was a. Transistors b. Vacuum Tubes and Valves c. Integrated Circuits d. None of above
Last Answer : Vacuum Tubes and Valves
Description : First generation computer systems used 1) Transistors 2) Vacuum tubes 3) Magnetic cores 4) Silicon chips
Last Answer : 2) Vacuum tubes
Description : Which electronic component was use in first generation? 1) Vacuum tubes 2) transistors 3) IC chips 4) all above
Last Answer : 1) Vacuum tubes
Description : Which electronic component was use in first generation? 1 Vacuum tubes 2 transistors 3 IC chips 4 all above
Last Answer : 1 Vacuum tubes
Description : In electronic computers, vacuum tubes were replaced by transistors and transistors have been replaced by what device?
Last Answer : Integrated circuits.
Last Answer : b. Vacuum Tubes and Valves
Description : The purpose of a heat sink, as frequently used with transistors, is to ____________. A. prevent excessive temperature rise B. compensate for excessive doping C. increase the reverse current D. decrease the forward current
Description : The use of four diodes, in a full-wave bridge rectifier circuit, will __________. A. provide unidirectional current to the load B. allow a very high leakage current from the load C. convert direct current to alternating current D. offer high opposition to current in two directions
Description : What are the advantages of freewheeling diodes in a controlled in a controlled rectifier?
Last Answer : a. Input power factor is improved. b. Load current waveform is improved and thus the load performance is better.
Description : What is the function of freewheeling diodes in controlled rectifier?
Last Answer : It serves two process. a. It prevents the output voltage from becoming negative. b. The load current is transferred from the main thyristors to the freewheeling diode, thereby allowing all of its thyristors to regain their blocking states.
Description : What resistance property is found in tunnel diodes but not in normal diodes?
Last Answer : Negative resistance.
Description : What is the main difference in construction between normal PN junction diodes and tunnel diodes?
Last Answer : The amount of doping.
Description : What causes the negative-resistance property of tunnel diodes?
Last Answer : The tunneling action
Description : In which region is the operating point stable in tunnel diodes? (1) Negative-resistance (2) Positive-resistance (3) Both negative- and positive-resistance (4) Neither negative- nor positive-resistance
Last Answer : In Negative-resistance region is the operating point stable in tunnel diodes.
Description : Normally, the FIRST step in troubleshooting a transistor circuit card is to _____________. A. carefully remove the transistors from the card B. give the circuit an initial test with a signal generator C. test for continuity with a low voltage DC supply D. visually inspect the card
Description : The number of diodes used in bridge rectifier circuit is (a) 4 (b) 3 (c) 2 (d)
Last Answer : (a) 4
Last Answer : Bridge rectifier requires four diodes
Description : To avoid damaging the components of a printed circuit board when testing it with a DC volt-ohmmeter, you should _______. A. ground the board B. avoid reversing the polarity of the leads C. isolate sensitive components with heat sinks D. all of the above
Description : Which of the listed conditions describes the effect on intrinsic semiconductor operation as a result of a temperature increase? A. Additional heat sinks will be required B. Conductivity will increase C. Conductivity will decrease D. Resistivity will increase
Description : The method used to produce electron emission in most vacuum tubes is known as ____________. A. photoelectric emission B. secondary electric emission C. cold cathodic electric emission D. thermionic emission
Description : A device used in an electrical circuit to change alternating current to direct current, is known as a _____________. A. current transformer B. rectifier C. condenser D. shunt
Description : Component 'B' of section 'I' shown in the illustration represents a _____________. EL-0093 A. bridge rectifier B. selsyn motor C. small generator D. shielded lamp
Last Answer : Answer: C
Description : Section IV of the circuit shown in the illustration is the _____________. EL-0085 A. voltage regulator B. filter C. rectifier D. voltage transformer
Description : Basically, a magnetic amplifier is a saturable reactor with the addition of _____________. A. AC to the bias winding B. variable capacitance to all windings C. eddy current protectors D. a rectifier in the load circuit
Description : Section III of the circuit shown in the illustration is a _____________. EL-0085 A. voltage regulator B. filter C. rectifier D. voltage transformer
Description : Since the characteristics of the device shown in figure 'A' of the illustration includes a stable voltage and low current while operating, it can be suitably used in _____________. EL-0065 A. oscillators ... . class A and B amplifiers C. generator rectifier and filtering supplies D. all of the above
Description : Which of the following is not a feature of first generation computers A) They used vacuum tubes or valves as main electronic component B) They consumed lots of electricity and produced excessive heat C) They used machine language and assembly language to program the machine D) None of above
Description : What was the main disadvantage of vacuum tubes? A) They were larger in size B) They consumed a lot of electricity C) They produced heat and often burned out D) The operation cost was high
Description : All electric cables passing through watertight bulkheads must be _____________. A. installed with watertight stuffing tubes B. grounded on both sides of the bulkhead C. fitted with unions on each side of the bulkhead D. welded on both sides of the bulkhead
Description : Which of the following was used as circuitry for first generation of computers? (1) Vacuum tube (2) Transistors (3) Integrated circuits (4) Microprocessors
Last Answer : Vacuum tube
Description : The main difference between an electron tube and a transistor is the _____________. A. type of function they can perform B. reaction of electron flow through a gas or vacuum in a transistor C. ... when placed in a tube D. reaction of electron flow through a semiconductor used to form a transistor
Description : An important characteristic of the device shown in figure 'B' of the illustration as compared with conventional NPN or PNP transistors is its ____________. EL-0065 A. higher temperature sensitivity B. higher power ratings C. very high input resistance D. all of the above
Description : When checking the specific gravity of the battery electrolyte with a hydrometer, you should be aware that ________________. A. the battery is fully charged when the float sinks deepest into the ... is added to the cell D. warm temperatures will lower the specific gravity of the electrolyte
Description : Calcium ammonium nitrate (a fertiliser) is dried in a __________ dryer. (A) Rotary (B) Vacuum (C) Tunnel (D) Tray
Last Answer : (A) Rotary
Description : Drying of refractory is normally carried out in a __________ dryer. (A) Open pan (B) Tray (C) Rotary vacuum (D) Truck/tunnel
Last Answer : (D) Truck/tunnel
Description : Unnecessary and frequent applications of varnish to the generator windings to repair defective insulation will result in ____________. A. heavy coatings of varnish interfering with heat dissipation B. ... of the rectifier assembly D. a built-up of varnish without changing generator operation
Description : Power transistors with heat sink are fixed by
Last Answer : Power transistors with heat sink are fixed by Fastening
Description : In the illustrated circuit, if the input to leads 'B' and 'Y' was 24 VDC the output between 'A' and 'X' will be _________. EL-0069 A. 24 VDC B. 22.8 VDC, 24 VDC minus the 1.2 VDC voltage drop across two diodes C. undeterminable without knowing the turns ratio of the transformer D. 0 VDC
Description : Routine maintenance of a ship's service alternator should include ______________. A. changing the pedestal bearing insulation yearly B. megger testing of all rectifying diodes C. lubricating excitation slip rings D. periodic cleaning of the air filters or screens
Description : What types of inverters require feedback diodes?
Last Answer : VSI with RL load.