# time base generators

explain methods of generating time base waveform

time base generator generate high frequency sawtooth waves.
Methods for generating time base waveforms
1. bootstrap circuit
2. Miller circuit
3. exponential charging

## Related questions

Description : Draw the circuit diagram of Bootstrap’s time base generator and explain its working.

Answer : Circuit Diagram Waveform: Here transistor Q1 acts as a switch and transistor Q2 acts as an emitter follower (i.e. a unit gain amplifier).  Circuit Operation: Initially transistor ... The circuit pulls itself up by its own bootstrap and hence it is known as bootstrap sweep circuit.

Description : Justify the need of current time base generator to obtain the specified sawtooth waveform with one example.

Answer : Justification:- * Current Time base generator is a circuit where the output current is a linear function of time over a specified time interval. * Time base circuits are used by radar systems to determine ... the time. * The diode D does not conduct during the sweep, because it is reverse biased.

Description : The time base signal in Cathode Ray Oscilloscope (CRO) is  (1) A square wave signal (2) A sawtooth signal (3) A triangular wave signal (4) A sinusoidal signal

Answer : In CRO the time base signal is applied to: X-plates

Description : Why are generators rated in kVA not in kW ?

Answer : Because It's rating of generator kva is apparent power. Kw is active power which we use. And one is kvar reactive power.

Description : Classify different types of generators.

Answer : Different Types of Generators:  1) Separately excited DC generator  2) Self excited DC generator: (i) DC series generator (ii) DC shunt generator (iii) DC Compound generator: short shunt and long shunt / (cumulative or differential)

Description :  Which of the following generators is used for DC arc welding application ? (A) Series generator (B) Shunt generator (C) Differential compound generator (D) Over -compound generator

Description : What is the other name used for DC generators? A. Dynamos B. Alternator C. Capacitor D. Dynamotor

Answer : Dynamos is the other name used for DC generators.

Description : Polyphase generators produce simultaneous multiple sinusoidal voltages that are separated by certain constant: A. Phase -angles B. Frequency C. Voltage D. Current

Answer : Polyphase generators produce simultaneous multiple sinusoidal voltages that are separated by certain constant: Phase -angles

Answer : The most appropriate operating speed in rpm of generators used in Thermal, Nuclear and Hydro-power plants would respectively be: 3000, 3000 and 300

Description : Consider efficiencies of hydro-turbines and generators. If the efficiency of a hydro-turbine is 80% and the efficiency of a generator is 90%, what is the overall efficiency of the unit? w) 85% x) 72% y) 90% z) 70%

Description : Recommend with justification the generators used in SWT.

Answer : 1. Fixed Speed Induction Generator: This is squirrel cage induction generator for fixed speed. This is 1) reliable 2) self-starting 3) easy to adjust 4) have low maintenance.  2. ... optimizes use of given grid capacities 6) Better cooling performance 7) Reduced noise level of moving parts.

Description : List various types of generators used in WPP.

Answer : Various Types of Generators Used in WPP: 1. Squirrel Cage Induction Generator ( SCIG ) 2. Wound Rotor Induction Generator ( WRIG ) 3. Doubly Fed Induction Generator ( DFIG ) 4. Wound Rotor synchronous Generator ( WRSG) 5. Permanent Magnet Synchronous Generator ( PMSG)

Description : Two 3-phase synchronous generators with reactance 60% and 40% feed a fault current of 1200 A up to short-circuit fault point. The short-circuit current is (A) 1200 A (B) 2400 A (C) 4000 A (D) 5000 A

Description : Shunt generators are most suited for stable parallel operation as their voltage characteristics are (a) drooping (b) identical (c) linear (d) rising

Description : Two synchronous generators G1, G2 are operating in parallel and are equally sharing KVAR (Lag) component of load. To shift part of KVAR from G2 to G1, while keeping terminal voltage fixed, the following action must be done

Answer : Two synchronous generators G1, G2 are operating in parallel and are equally sharing KVAR (Lag) component of load. To shift part of KVAR from G2 to G1, while keeping terminal voltage fixed, the following action must be done Raise If1 and lower If2

Description : Identify the increasing order of voltage regulation of the following dc generators a same load :  (A) differential compound, shunt and under compound  (B) shunt, differential compound and ... C) under compound, shunt and differential compound  (D) shunt, under compound and differential compound

Answer : Identify the increasing order of voltage regulation of the following dc generators a same load : under compound, shunt and differential compound

Description : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, ... system frequency is (A) 50 Hz (B) 51 Hz (C) 51.25 Hz (D) 51.5 Hz

Answer : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency is 50 Hz

Description : In signal generators - a) energy is created b) energy is generated c) energy is converted from a simple DC source into ac energy at some specific frequency d) all the above

Answer : In signal generators - energy is converted from a simple DC source into ac energy at some specific frequency

Description : In DC generators, armature reaction is produced by the: (A) field current (B) armature conductors (C) field pole winding (D) load current in armature

Answer : In DC generators, armature reaction is produced by the: load current in armature

Description : Name the types of generators (alternators) used in (1) thermal plant and (2) in hydel power plant.

Answer : If  equalising bar is connected to the 2 DC generators  the current will be equal in 2 generators irrespective of parallel connection so that we connect equaliser bar

Answer : In D.C. generators on no-load, the air gap flux distribution in space is flat topped.

Answer : In D.C. generators the polarity of the interpoles is the same as that of the main pole ahead.

Answer : For the parallel operation of two or more D.C. compound generators, we should ensure that series fields of all generators should be either on positive side or negative side of the armature.

Answer : In D.C. generators, lap winding is used for low voltage, high current.

Answer : Compensating windings are used in D.C. generators to neutralise the cross-magnetising effect of the armature reaction.

Answer : D.C. generators are connected to the busbars or disconnected from them only under the floating condition to avoid sudden loading of the primemover, to avoid mechanicaljerk to the shaft, to avoid burning of switch contacts.

Answer : In D.C. generators, the brushes on commutator remain in contact with conductors which lie under interpolar region.

Answer : In D.C. generators, current to the external circuit from armature is given through commutator commutator.

Answer : In D.C. generators the pole shoes are fastened to the pole core by counter sunk screws.

Answer : D.C. generators are installed near the load centres to reduce line losses.

Answer : D.C. generators are normally designed for maximum efficiency around full-load.

Answer : Large capacity generators are invariably hydrogen cooled.

Answer : Generators for peak load plants are usually designed for maximum efficiency at 50 to 75 percent full load.

Description : In DC generators lamination core are generally made of?

Answer : In DC generators lamination core are generally made of silicon steel.

Description : Select insulating materials for following parts : (i) Insulation between heating element and base plate of electric iron. (ii) Insulation used over copper or aluminium conductor used for making coils. (iii) Transformer bushings. (iv) Insulation between transmission line and pole.

Answer : Parts Insulating Materials  Insulation between heating element and base plate of electric iron. Mica Insulation used over copper or aluminium conductor used for making coils.  ... Transformer bushings Porcelain  Insulation between transmission line and pole. Porcelain

Description : Define the following terms : (i) Base Station (ii) Control Channel (iii) Mobile Station (iv) Page

Answer : i) Base Station: - A fixed station in a mobile radio system used for radio communication with mobile stations. Base stations are located at the center or on the edge of a coverage region ... the page throughout the service area using base stations which broadcast the page on a radio carrier.

Description : Compare base load plant with peak load plant on any two points.

Answer : Points Base load plant Peak load plant Definition The power plant which supplies base load of load curve is known as base load plant  The power plant which supplies ... ,thermal,nuclear power station Small capacity storage hydro,pumped storage hydro,gas,diesel power station.

Description : State why nuclear power plants are used as base load plants and diesel power plants as a peak load plant.

Answer : 1. Because of following points Nuclear power plant used as base load power plant:-  1. Nuclear power plants is very economical for producing bulk amount of electric power 2. Nuclear power plant is reliable ... . The plants can be put on load easily. 4. Diesel engines take less time to make OFF.

Description : Compare BJT common base configuration with common collector configuration on the basis of (i) Current gain (ii) Voltage gain (iii) Input impedance (iv) Output impedance

Answer : Parameter Common Base Common Collector Current gain Low (About 1) High (1+β) Voltage gain High 1  Input impedance  Low High Output impedance High Low

Description : In short circuit calculations, the selected base kVA is equal to (A) That of the largest Plant (B) The total plant Capacity (C) Any arbitrary value (D) Can be any one of (A), (B), (C)

Description : Which of the following is not a base load plant ? (A) Thermal power plant (B) Pumped storage plant (C) Hydro power plant (D) Geothermal power plant

Description : Short-circuit kVA is obtained by multiplying the base kVA by (1) 10% X (2) 20% X (3) 50% X (4) 100% X

Description : The per unit impedance of a circuit element is 0.30. If the base kV and base MVA are halved, then the new value of the per unit impedance of the circuit element will be:  (A) 0.3 (B) 0.6 (C) 0.003 (D) 0.006

Description : State the condition for no tension at the base of a column.

Answer : If the load acting in the middle third area or core of the section, then the material experiences only compressive stress without producing tensile stress. i.e. Direct stress is equal to bending stress. Minimum stress is zero, such condition is said to be no tension condition.

Description : What are the two we use to query and answer in knowledge base?

Description : Define a knowledge Base:

Answer : Knowledge base is the central component of knowledge base agent and it is described as a set of representations of facts about the world.

Description : From base load operation and from achieving best specific energy consumption point of view, which of the following compressors are suitable? a) Single stage reciprocating compressors b) Centrifugal compressors c) Two stage reciprocating compressor d) Multi stage reciprocating compressor