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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
What is the difference between inductive coupling and capacitive coupling?
A capacitor is a device that resists a change in voltage, proportional to current and inversely proportional to capacitance.
dv/dt = i/c
An inductor is a device that resists a change in current, proportional to voltage and inversely proportional to inductance.
di/dt = v/l
In an AC circuit with capacitive loading, the current waveform will lead the voltage waveform; while with inductive loading, the current waveform will lag the voltage waveform.
What are the advantages of PIC micro-controller over 8051?
In general, personal preference and experience is what it comes down to. There are some PIC's that have built in RF systems; I don't believe there are any 8051's with this capability.
The essential guideline behind the working of a zener diode lies in the reason for breakdown for a diode in converse one-sided condition. Typically there are two sorts of breakdown-Zener and Avalanche.
1.) Zener Breakdown
This sort of breakdown happens for a converse inclination voltage between 2 to 8V. Indeed, even at this low voltage, the electric field power is sufficiently solid to apply a power on the valence electrons of the molecule such that they are isolated from the cores. This outcomes in development of portable electron gap sets, expanding the stream of current over the gadget.
This sort of separate happens regularly for profoundly doped diode with low breakdown voltage and bigger electric field. As temperature builds, the valence electrons acquire vitality to disturb from the covalent bond and less measure of outside voltage is needed. Hence zener breakdown voltage diminishes with temperature.
2.) Torrential slide breakdown:
This kind of breakdown happens at the converse inclination voltage over 8V and higher. It happens for delicately doped diode with vast breakdown voltage. As minority charge bearers stream over the gadget, they have a tendency to crash into the electrons in the covalent bond and reason the covalent bond to upset. As voltage expands, the active vitality of the electrons additionally increments and the covalent bonds are all the more effectively upset, creating an increment in electron opening sets. The torrential slide breakdown voltage increments with temperature.
According to Ohm's law of resistance in parallel, 1/RT=1/R1+1/R2+1/R3... so 1/RT=1/12+1/4=1/12+3/12=4/12=1/3 and 1/(1/3)=3.
The total resistance of the two devices is 3.
There is a simpler special case formula for two resistances in parallel:
* RTot = (R1R2) / (R1 + R2) In this case this it would give us (12 x 4) / (12 + 4), or 48 / 16 which equals 3 ohms.
3 ohms
Thévenin's theorem for linear electrical networks states that any combination of voltage sources, current sources, and resistors with two terminals is electrically equivalent to a single voltage source V and a single series resistor R #wikipedia
actually i will explain you the way to solve problems applying this theorem consider a large network and in that network assume any resistance R about which you are asked o find the current and voltage-drop. now follow the steps below carefully
1. remove the specific resistor from the circuit (open the resistor) and find the voltage across both the points(or even parallel to both the points) where the resistor is opened this is called VTH (this is called thevenin's voltage).Also dont forget to open the current sources if present.
2. now to calculate the effective resistance as seen from the opened resistor short all the voltage sources and open all the current sources. and assume an arbitrary voltage V in the place of the opened resistor find current through the branch by mesh analysis and the ratio of voltage and current gives you the effective resistance fo the circuit as seen from the opened resistor. this is called Rth (thevenin resistance).
now , after getting the values of VTH,RTH construct a circuit in which the given resistance R and RTH arein series with the voltage source VTH , and the so called found current is the current flowing through R in the actual circuit
What is the difference between dual fiber single mode and dual fiber multi mode?
There are 2 major differences one color code. single mode will be white or yellow. multimode will be black or tan. 2nd the hole in the connector ferrel for the fiber. fiber is 125 microns. in a single mode connector the opening is 126 microns. multimode is 127/128.
Single Mode cable is a single strand (most applications use 2 fibers) of glass fiber with a diameter of 8.3 to 10 microns that has one mode of transmission. Single Mode Fiber with a relatively narrow diameter, through which only one mode will propagate typically 1310 or 1550nm. Carries higher bandwidth than multimode fiber, but requires a light source with a narrow spectral width. Synonyms mono-mode optical fiber, single-mode fiber, single-mode optical waveguide, uni-mode fiber.
Single Modem fiber is used in many applications where data is sent at multi-frequency (WDM Wave-Division-Multiplexing) so only one cable is needed - (single-mode on one single fiber)
Single-mode fiber gives you a higher transmission rate and up to 50 times more distance than multimode, but it also costs more. Single-mode fiber has a much smaller core than multimode. The small core and single light-wave virtually eliminate any distortion that could result from overlapping light pulses, providing the least signal attenuation and the highest transmission speeds of any fiber cable type.
Single-mode optical fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest typically 1300 to 1320nm.
Multi-Mode cable has a little bit bigger diameter, with a common diameters in the 50-to-100 micron range for the light carry component (in the US the most common size is 62.5um). Most applications in which Multi-mode fiber is used, 2 fibers are used (WDM is not normally used on multi-mode fiber). POF is a newer plastic-based cable which promises performance similar to glass cable on very short runs, but at a lower cost.
Multimode fiber gives you high bandwidth at high speeds (10 to 100MBS - Gigabit to 275m to 2km) over medium distances. Light waves are dispersed into numerous paths, or modes, as they travel through the cable's core typically 850 or 1300nm. Typical multimode fiber core diameters are 50, 62.5, and 100 micrometers. However, in long cable runs (greater than 3000 feet [914.4 meters), multiple paths of light can cause signal distortion at the receiving end, resulting in an unclear and incomplete data transmission so designers now call for single mode fiber in new applications using Gigabit and beyond.
More Information:
Multimode and Singlemode fiber are the five types of fiber in common use. Both fibers are 125 microns in outside diameter - a micron is one one-millionth of a meter & 125 microns is 0.005 inches- a bit larger than the typical human hair. Multimode fiber has light travelling in the core in lots of rays, called modes. It's a bigger core (always 62.5 microns, but sometimes 50 microns) & is used with LED sources at wavelengths of 850 & 1300 nm for slower local area networks (LANs) & lasers at 850 & 1310 nm for networks jogging at gigabits per second or more. Singlemode fiber has a much smaller core, only about 9 microns, so that the light travels in one ray. It is used for telephony & CATV with laser sources at 1300 & 1550 nm. Plastic Optical Fiber (POF) is large core (about 1mm) fiber that can only be used for short, low speed networks.
Step index multimode was the first fiber design but is slow for most makes use of, due to the dispersion caused by the different path lengths of the various modes. Step index fiber is rare - only POF makes use of a step index design today.
Graded index multimode fiber makes use of variations in the composition of the glass in the core to compensate for the different path lengths of the modes. It offers hundreds of times more bandwidth than step index fiber - up to about 2 gigahertz.
Singlemode fiber shrinks the core down so small that the light can only travel in one ray. This increases the bandwidth to infinity - but it is practically limited to about 100,000 gigahertz.
Why input resistance of voltage amplifier is infinity?
For the successful amplification of the input signal the opamp should have ideally infinite input impedance . It should act like a buffer amplifier
BUFFER amplifier--------------------->
1.input impedance infinity
2.output impedance zero
the reason is that
Any signal source will have source impedance
for the signal not to get lost and dropped across source impedance we ideally insert infinite impedance in series with it which makes the whole drop across the infinite impedance but not across the source
similarly at the output zero impedance is used where in no part of the signal should be left behind in the op amp as a drop
integrated circuit
Difference between instrumentation and operational amplifiers?
An instrumentation amplifier is made out of 2 or 3 operational amplifiers.
Describe forward-biased diode?
A specific amount of current is allowed to flow through a diode. If the current passing through the diode exceeds this specific value, the diode gets heated and is likely to be damaged. Therefore, in the biasing circuit of a resistance which limits the current passing through the diode within its specific value is called Forward biased diode.
ANSWER: A forward bias diode is just a diode that it is conducting in the forward direction. Positive to anode and negative to cathode
What is the voltage drop running through resistor one?
What is the voltage drop running through resistor one
How can convert a full adder to a full subtractor with circuit?
let us consider three inputs a,b,c and their sum as s, difference as d and carry as c and borrow b
in full adder circuit :-
s= a (XOR) b (XOR) c
carry = ab+ac+bc
in full subtractor :-
d= a (XOR) b (XOR) c
borrow b = a'b+a'c+bc
so on observing these two we notice that sum and difference are one and the same coming to carry and borrow the only difference is to obtain borrow from carry just complement the input a
What is the function of input and output coupling capacitors CC1 and CC2?
We don't know much about the circuit these capacitors are in, but they are coupling capacitors. Coupling capacitors isolate DC between stages or circuits, and they couple AC between those circuits or stages. Only the signal gets in and goes out. The DC the stage operates on is isolated from stage to stage.
mainly i will tell ttwo advantages:-
1)in FET "thermal runaway" never occurs but in bjt it occurs easily...thermal runaway means overheating and damage of fet due to different biasing voltages..
2) since FET is a unipolar device so only one carrier type is required here ,but bjt is a bipolar device ..
3) FET is smaller in size than BJT of same rating. i mean to say that at the place of 10 bjts we can use 90 FETs ..so area cosumption is less
What is difference between line current and phase current?
A phase current is the current passing through a phase, whereas a line current is the current flowing through a line.
In the case of a balanced delta-connected load, IL = 1.732 IP. In the case of a balanced star-connected load, IL = IP.
For unbalanced loads, these relationships don't hold true, and must be individually calculated.
Why can't we implement the center tapped full wave rectifier without center tapped transformer?
A center-tapped transformer and two diodes can form a full-wave rectifier that allows both half-cycles of the AC waveform to contribute to the direct current, making it smoother than a half-wave rectifier. This form of circuit saves on rectifier diodes compared to a diode bridge, but has poorer utilization of the transformer windings. Hence we do not use centre tapping for full wave rectification.
Ashish sharma
Astt. Professor
HIET, Shahpur, kangra(H.P.)
What is the difference between flow control and congestion control?
Flow control vs. congestion control:
Flow control means preventing the source from sending data that the
sink will end up dropping because it runs out of buffer space.
This is fairly easy with a sliding window protocol--just make sure
the source's window is no larger than the free space in the sink's
buffer. TCP does this by letting the sink advertise its free buffer
space in the window field of the acks.
Congestion control means preventing (or trying to prevent) the
source from sending data that will end up getting dropped by a
router because its queue is full. This is more complicated, because
packets from different sources travelling different paths can
converge on the same queue.
What is ohm's law expressed as a formula?
Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points, and inversely proportional to the resistance between them
The current would be about 20 volts.
Why does an inductor block AC but allow DC?
While it is true that an inductor opposes the flow of an alternating current, it does not necessarily 'block it'. The quantity that opposes the flow of an AC current is the inductor's inductive reactance, expressed in ohms. Inductive reactance is proportional to the frequency of the supply voltage and, at 50 or 60 Hz, the reactance of a transformer's winding is relatively low (although very much higher than its resistance) and, while this acts to limit the amount of current flow, it certainly doesn't act to block that flow.
6 Which file system is used by floppy disks?
Any file system can be used by a floppy disk, as long as the minimum partition size of the file system does not exceed the capacity of the floppy. FAT12 is the most common on Windows / MS-DOS computers. AFS was common on earlier Macs. ext was used among many Linux users. Floppy disks can use a variety of file systems. On MS-DOS and Windows computers, the primary file system for floppies is FAT12. On older Macs, the file system was HFS or MFS. Linux computers sometimes use ext.
How much power is consumed by a 6 ohm load with 12 volts applied?
Volts = Amps x Resistance
Therefore
Amps = Volts / Resistance
