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Electronics Engineering
Electronics Engineering is a branch of engineering that deals with practical applications of electronic components, devices, systems, or equipment. Electronics are devices that operate on low voltage sources, as in electron tubes, transistors, integrated circuits, and printed circuit boards and use electricity as part of its driving force.
24,372 Questions
The "LM" stands for Linear Monolithic" and is just part of the part-number that National decided to use for this famous timer IC.
The LM prefix is still used for a lot of medium complexity analog chips, like regulators and op-amps.
What is the principle or theory behind this dead weight gage tester?
Dead weight testers are named so because they utilize dead weights in determination of pressures operating in a closed and compressed fluid system. They are so called because of the reason that for each value of pressure to be exerted/ applied in the closed hydraulic system, a predetermined / fixed amount of weights are used to exert the force to counter balance the buoyancy forces. Each weight is stamped with the equivalent amount of force that will be exerted on a predetermined area of piston cylinder arrangement by using that weight. There fore the device is called Dead Weight tester.
Working Principle: DWT (Dead Weight Tester) works based on the principle of Pascal's law. The law states that in a closed system of incompressible fluid, the pressure applied will exert equal amount of force in all the directions.
In DWT system, silicon oil is used within the closed boundaries of the Piston cylinder arrangement, piping, pressurisation chamber and in the head on which the gauge to be tested/ calibrated is fixed. The oil is taken in to the pressurisation chamber from oil bowl and all the air entrapped is vented off. This is because of the reason that air is compressible and hence do not allow pressure to be exerted equally in all the areas and there by create error in the test results. Once the system is full with air free oil, pressure is gradually increased from the pressurization chamber. Oil pressure starts increasing in all the areas including piston cylinder arrangement over which the dead weights are mounted. As the force increases gradually and equals the amount of down ward force being exerted by the dead weights, the total system gains the state of equilibrium and just at that moment, the dead weights starts getting lifted up. At this condition, the amount of force operating in the entire system is same. The sum of pressure values stamped on weights lifted is operating on the pressure gauge element also, which is under test/ to be calibrated. Necessary corrections are made in the zero/ span adjustments in gauges/ Pressure transmitters. Above sequence is repeated for all the values at 0%, 25%,50%,75% and 100% to check for linearity and repeatability.
This is how the DWTs are working.
What are differences between broadside array and end fire array?
end fire array
A combination of identical and equally spaced antenna that radiate along the axis of the axis of the antenna array is known as an end fire array.
the elements are fed with a current of equal magnitude but opposite in phase.due to this variation in phase ,the radiation obtained is unidirectional.
broadside array
when the maximum radiation of an array is directed normal to the axis of array it is known as broadside array.
in a broadside array combination a number of identical antennas are set up along a line drawn perpendicular to their respective axis.
Why is omega symbol used for ohms?
The first letter of the word Ohms is O. The equivalent letter in the Greek alphabet, is Omega.
What does open collector output mean?
Open collector output is normally used in logic circuits and can be viewed as a common emitter configuration for a BJT transistor and normally of type NPN. A typical common emitter configuration requires the emitter to be connected to the ground and a resistor Rc from Vcc to the collector. When the transistor becomes forward biased, the collector will pulled the voltage across the resistor down, from approximately Vcc down to almost 0V, normally in the order of 0.1V at the collector.
We can see that the output at the collector will swing between Vcc and ground. In open collector outputs the collector resistor Rc and Vcc have been left out. This enables the engineer to use any voltage and any pull-up resistor that will meet the specifications of the output transistor.
Normally it is acceptable in logic circuits that multiple inputs may be connected to one output, but not multiple outputs to one input due to the nature of the active outputs. With open collectors however multiple outputs may be connected to one input without damaging the device.
Low state will result in a lower impedance than a high state since the high state is obtained by current flowing from Vcc through the pull-up resistor Rc.
Open collector can be used to convert 5V logic to 8V or 12V logic or down to 3.3V since the logic high will be determined by the external supply to the pull up resistor.
Open collector also prevents component failure during output short-circuit or over-current. If an open collector is short circuited to the ground, it will cause no harm to the device since all the current will be supplied via the Rc resistor. Short circuit to a +supply rail can however damage the device.
Open collector is not used that commonly anymore but many variations of the same concept can be found in modern electronics. For example: micro processor devices that employ a I2C (Inter-Integrated Circuit) communications interface make use of a open-drain lines.
It appears to work very much in the same fashion with pull-up resistors and all. Open drain is associated with MOSFET transistors instead of BJT's. In this example an I2C interface will fail if pull-up resistors are not used. Like open collector, open drain lines are also passive and does not provide any active high output of its own. The High output is supplied by Vcc via the Rc or Rp pull-up resistors. The open collector or open drain will pull the pull-up resistor voltage down to the ground to create a low impendence, low logic state.
When people talk about 480V systems, they mean 480 is the RMS voltage.
What is meant by cut in voltage in diode?
Cut in voltage (Knee voltage): The forward voltage at which the current through the P-N Junction starts increasing rapidly is called as Cut in voltage or knee voltage.
A: It is a 14 pins dual in line quadruple 2 input positive NOR Gates. It BELONG TO THE 74XX family of IC
What is the difference between thermocouple and thermostat?
A thermocouple is a device which generates an electrical charge when
heated. It is often used on a boiler to indicate that the pilot light
is on and hot, so it should be safe to allow gas to pass to the main
burner for heating water, your house, etc. Should the pilot light go
out, the thermocouple will sort of "tell" the boiler to shut off the
gas, as it isn't safe to fire up.
A thermostat is used as a switch, which goes on and off at a certain
temperature. For example, in a boiler it will tell the boiler that the
water in the circuit is plenty hot enough and that it doesn't need to
be heated any more, in your house it will tell your central heating
that the room is warm enough and doesn't need heating any more and in
your car it would say that your engine is too hot and that the radiator
valve should open, and perhaps the cooling fan should turn on.
It is a Butyro Refrective Index meter. Generally, it is used by Dairy Industry to measure the Brix of oil present in the milk. Milk oil basically are present in the BR range of 40-43. This BR set up is specially used to check adulteration in milk, if adulterated with external oil to increase the fat percentage in the milk.
What is the procedure to issue the gate pass in a company?
Proper procedure of Issuing of Gate passes in a company
1. When a visitor reaches to the location the guard at the access point is to inquire the requirement.
2. Guard is to request the visitor to produce the National Identity card for the proper identification.
3. After the identification, the guards is to inform the matter to the relevant official to get permission for access.
4. After obtaining permission from official guard is to enter the details of the visitor in the visitors passes issuing register and get the signature of the visitor.
5. Guard then issues the relevant visitor pass (there may be color code system with passes) and should instruct to wear it either on left pocket of the shirt or center chest area of the dress.
6. Important; Each pass must numbered properly and passes are to be placed in a pigeon hole rack. after issuing each pass the ID card is to place in the same pigeon hole.
7. When visitor return back to guard room, the guard is to check the register and ask him to put the signature to confirm that he has reach at the exit point safely.
8. After obtaining the entry permit pass, check the pass number and guard is to issue the ID card which was kept in the pigeon hole.
What happen if a prime mover fails when two generators are in parallel?
It acts as synchronous motor by consuming power from the other generator....
What are the necessary conditions for turning ON an silicon controlled rectifier?
A: Two conditions one the gate has current flowing trough the other is forward voltage breakdown
What does gm0 represent in a BJT amplifier circuit?
gm0 is not used in BJT amplifier circuits; it is used in JFET circuits. It is the transconductance at zero gate bias. Since the transconductance varies as the bias is varied, this gives a benchmark level at a given defined point, and other transconductances can be calculated from it as a function of the amount of negative bias on the gate. If it were linear it would be the same everywhere, but it is not.
What is the use of the oscilloscope?
If you use a voltmeter to observe a voltage, it can only respond slowly, so if you want to observe a voltage that changes in fractions of a microsecond, you need a voltmeter that can respond at such speeds. It is called an oscilloscope.
In the fixed.bias biasing several key parameters of the amplifier depend on the Beta of the transistor. This parameter has a wide variation (often 5 to 1 or more) for a particular transistor type. Thus, if you need to make a production run of a number of identical amplifiers, this variation in the Beta is unacceptable.
In the voltage-divider stabilized method the performance of the amplifier is independent of Beta (or almost). Thus, this design is suitable to be used in the production of a large number of identical devices.
In terms of biasing, a voltage divider circuit helps offset the effect of changes in the beta value of the transistor. So it's said to be more 'stable' because heating of the transistor, or swapping transistors entirely (both of which affect beta) will not greatly affect the output of the circuit.
As far as the actual output is concerned, I believe both circuits have similar input/output impedance ranges and similar voltage gains. But the fixed biased circuit typically has more current gain.
Induced Current and Motional Emf
The electric field in the metal bar causes a potential difference of V = El = vBl. If the bar slides along metal rails, as in the figure below, a closed circuit is set up with current flowing in the counterclockwise direction, up the bar and then around the metal rail back to the bottom of the bar. TInduced Current and Motional Emf
The electric field in the metal bar causes a potential difference of V = El = vBl. If the bar slides along metal rails, as in the figure below, a closed circuit is set up with current flowing in the counterclockwise direction, up the bar and then around the metal rail back to the bottom of the bar. This is called an induced current.
The moving bar is a source of an electromotive force, called motional emf, since the emf is generated by the motion of the bar.
The force is defined as:
The magnitude of the induced emf can be increased by increasing the strength of the magnetic field, moving the bar faster, or using a longer bar.
Example
A bar of length 10 cm slides along metal rails at a speed of 5 m/s in a magnetic field of 0.1 T. What is the motional emf induced in the bar and rails?
Now that we've defined motional emf, solving this problem is simply a matter of plugging numbers into the appropriate equation:
his is called an induced current.
AC chopper is also called AC voltage controller. In AC voltage controller, we use 2 thyristors as switching element. In AC chopper we use MOSFET or IGBT as switching element with diodes in bridge rectifier for bidirectional flow of current. This use of mosfet switch has the following advantages over thyristor:
* no separate firing circuit are needed for Mosfet ( it can be driven directly by interfacing it with MC) whereas firing circuits are needed for SCR.
*when the line current drops to zero SCR turns off due to natural commutation( when it reaches 172 deg) ; mosfet- user control - we can turn on and off as per our requirement.
* snubber circuit is needed for thyristor phase control method. By using mosfet in diode rectifier provides internal snubber
What is the significance of gain bandwidth product?
To determine the maximum gain a device can extract at that particular bandwidth
