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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 power consumption and power dissipation?
A: POWER consumption is total power usage power dissipation is wasted power in the form of heat, IR drop and so on.
When silicon is doped with phosphorous what type of semiconductor results?
it would be a n-type semiconductor because phosphorus has more valence electrons than silicon does.
What is the maximum length of a PS2 cable?
There are cables up to 50 feet for sale, but if you want to modify one yourself, you can make it as long as you want, if you have enough wire (try using telephone wire). You can also get wireless controllers, and wireless AV connections.
What engineering applications use second order derivatives?
Second order derivative is used in many fields of engineering. One of its application is used in solving problems related to dynamics of rigid bodies and in determination of forces and strength of materials.
Advantages of carry look ahead adder?
You use a look ahead carry adder to reduce the propagation delay effects caused by the ripple carry that would otherwise be used. With ripple carry, each stage is dependent on the preceding stage, and this is cumulative. With look ahead carry, the carries are computed in parallel, speeding up the overall process.
What are the advantages of using fiber optic cable?
1. Immunity to Electromagnetic Interference
Although fiber optics can solve data communications problems, they are not needed everywhere. Most computer data goes over ordinary wires. Most data is sent over short distances at low speed. In ordinary environments, it is not practical to use fiber optics to transmit data between personal computers and printers as it's too costly. Electromagnetic Interference is a common type of noise that originates with one of the basic properties of electromagnetism. Magnetic field lines generate an electrical current as they cut across conductors. The flow of electrons in a conductor generates a magnetic field that changes with the current flow. Electromagnetic Interference does occur in coaxial cables, since current does cut across the conductor. Fiber optics are immune to this EMI since signals are transmitted as light instead of current. Thus, they can carry signals through places where EMI would block transmission.
2. Data Security
Magnetic fields and current induction work in two ways. They don't just generate noise in signal carrying conductors; they also let the information on the conductor to be leaked out. Fluctuations in the induced magnetic field outside a conductor carry the same information as the current passing through the conductor. Shielding the wire, as in coaxial cables can reduce the problem, but sometimes shielding can allow enough signal leak to allow tapping, which is exactly what we wouldn't want.
There are no radiated magnetic fields around optical fibers; the electromagnetic fields are confined within the fiber. That makes it impossible to tap the signal being transmitted through a fiber without cutting into the fiber. Since fiber optics do not radiate electromagnetic energy, emissions cannot be intercepted and physically tapping the fiber takes great skill to do undetected. Thus, the fiber is the most secure medium available for carrying sensitive data.
3. Non Conductive Cables
Metal cables can encounter other signal transmission problems because of subtle variations in electrical potential. Electronic designers assume that ground is a uniform potential. That is reasonable if ground is a single metal chassis, and it's not too bad if ground is a good conductor that extends through a small building. However, the nominal ground potential can differ by several volts if cables run between different buildings or sometimes even different parts of the same building.
Signal levels in semiconductor circuits are just a few volts, creating a problem known as ground loop. When the difference in ground potential at two ends of a wire gets comparable to the signal level, stray currents begin to cause noise. If the differences grow large enough, they can even damage components. Electric utilities have the biggest problems because their switching stations and power plants may have large potential differences.
A serious concern with outdoor cables in certain computer networks is that they can be hit by lightning, causing destruction to wires and other cables that are involved in the network. Certain computer companies are aware of this problem and trying to solve it by having protective devices for wire circuits to block current and voltage surges.
Any conductive cables can carry power surges or ground loops. Fiber optic cables can be made non-conductive by avoiding metal in their design. These kinds of cables are economical and standard for many indoor applications. Outdoor versions are more expensive since they require special strength members, but they can still be valuable in eliminating ground loops and protecting electronic equipment from surge damage.
4. Eliminating Spark Hazards
In some cases, transmitting signals electrically can be extremely dangerous. Most electric potentials create small sparks. The sparks ordinarily pose no danger, but can be really bad in a chemical plant or oil refinery where the air is contaminated with potentially explosive vapours. One tiny spark can create a big explosion. potential spark hazards seriously hinder data and communication in such facilities. Fiber optic cables do not produce sparks since they do not carry current.
5. Ease Of Installation
Increasing transmission capacity of wire cables generally makes them thicker and more rigid. Such thick cables can be difficult to install in existing buildings where they must go through walls and cable ducts. Fiber cables are easier to install since they are smaller and more flexible. They can also run along the same routes as electric cables without picking up excessive noise.
One way to simplify installation in existing buildings is to run cables through ventilation ducts. However, fire codes require that such plenum cables be made of costly fire retardant materials that emit little smoke. The advantage of fiber types is that they are smaller and hence require less of the costly fire retardant materials. The small size, lightweight and flexibility of fiber optic cables also make them easier to be used in temporary or portable installations.
6. High Bandwidth Over Long Distances
Fiber optics have a large capacity to carry high speed signals over longer distances without repeaters than other types of cables. The information carrying capacity increases with frequency. This however, doesn't mean that optical fiber has infinit bandwidth, but it's certainly greater than coaxial cables. Generally, coaxial cables have a bandwidth parameter of a few MHz/km, where else the fiber optic cable has a bandwidth of 400MHz/km. (These figures are just approximations and do vary from cable to cable!) This is an important factor that leads to the choice of fiber for data communications. Fiber can be added to a wire network so it can reach terminals outside its normal range.
The three main advantages are:
Speed - Fibre-optic cable is capable of transmitting data at a MUCH faster rate than copper cable.
Signal - Copper cable loses signal readily with length, and has to be boosted at regular intervals. The signal in Fibre-optic cable doesn't deteriorate nearly as much over distance and requires less boosting.
Capacity - Copper cable (using analogue signals) can only carry ONE signal at a time. Fibre-optic cable (using digital signals) can carry many data 'streams' as you just encode each stream so it gets to the right destination.
How does a capacitor store energy?
The energy stored in a capacitor is almost entirely in the electric field produced between the plates. It takes energy from a battery or some other power source to move electrons to one of the plates and away from the other. This makes one plate positively charged and the other negatively charged. Electric field is produced in proportion to the charge per unit area on a plate, and this electric field is said to originate on positive charges and terminate on negative charges.
Energy stored in electric fields is proportional to the square of the electric field strength and the volume of the field.
The energy is transferred from the power source to the electric field through the rearrangement of electrical charges.
What would be the resistance of an ideal voltmeter?
The theoretical resistance (idea resistance) of an ammeter is zero. With a voltmeter, it's infinitely high.
In some analog meters the full scale deflection is produced by only about 50 microamps. Actually that does not change from ammeter to voltmeter, just the configuration of the meter's external "connection circuit"changes.
Simple ammeters are 'connected in series' devices. The resistance of such an ammeter must be kept very low because, if it were a high resistance, that would seriously limit the current allowed into the circuit and would impair the circuit's function.
Voltmeters are 'connected in parallel' devices. The theoretical resistance of a volt meter is very high, the higher the better. It is checking the potential between two points, so, to have the least effect on the circuit it is measuring, it must draw as little current as possible.
Name three tools that you can use to protect a system against ESD as you work on it?
ANSI/ESD S20.20 covers the requirements of an ESD control program.
The fundamental ESD control principles are:
- Ground all conductors, including personnel
- Insulators are high charging and cannot be grounded. Remove all non-essential insulators. Keep all process essential insulators at least 12" from ESDS or neutralize charges with ionizers
- Outside an EPA, ESDS are to be packaged in closed ESD shielding bags or covered containers having shielding properties
Grounding works great removing electrostatic charges. If opening a computer and handling circuit boards or electronics, the person should be grounded using a wrist strap connected to the ground of an AC electrical outlet or equipment ground. The ESD sensitive items should be placed on a grounded mat. A good tool to have is a Field Service Kit which includes a mat, a cord to ground the mat, and a wrist strap to ground the person.
If attachment to the ground of an AC electrical outlet is not possible, one can use equipotential bonding.
"When neither AC equipment [Equipment Grounding Conductor] or auxiliary grounds are available, an equipotential bonding system may need to be used. In this situation, all of the items in the system are bonded together so that the charge that resides on the elements will be shared equally and therefore there will be no potential difference between the items. Once this step has been completed it is safe to handle ESD sensitive parts without inducing damage. A real life example of this is often observed in office equipment field service operations. For safety reasons the service technician will often disconnect the AC power cord which detaches the equipment from ground. In order to safely install ESD sensitive products into the equipment, it is necessary to electrically connect or bond together the service technician, the equipment frame and the ESD sensitive product. Once bonded together an ESD event will NOT occur when the technician handles the product or installs it in the office equipment." [ESD Handbook ESD TR20.20-2008 section 5.1.3 Basic Grounding Requirements]
How do you convert analog signal to digital signal?
Various analog to digital converters are available for this purpose. They are basically made up of operational amplifiers.
The other way is to convert the analog signal into samples. Then converting these samples into quantization levels. These quantization levels are then converted into 1s and 0s.
Compare between center tap rectifier and bridge rectifier?
Parameter HWR FVR FVBR 1 No. of Diodes 1 2 4 2 Need of Centre tapping in secondary of the transformer winding No Yes No 3 Average dc voltage Edc Em/π 2Em/π 2Em/π 4 Average d.c. current Idc Im/π 2Im/π 2Im/π 5 RMS value of Current IRMS Im/2 Im/ Im/ 6 Ripple Factor γ 1.21 0.48 0.48 7 Ripple Frequency f 2f 2f 8 Maximum Rectification Efficiency η 40.6 % 81.2 % 81.2 % 9 Average Diode Current Idc Idc/2 Idc/2 10 Form Factor 1.57 1.11 1.11 11 Filtering Difficult Easy Easy 12 Voltage Drop in Diode Less Less More 13 PIV Em 2Em Em 14 T.U.F. (TRANSFORMER UTILISATION FACTOR) 0.287 0.693 0.812 15 Applications Less In low In High voltage Voltage rectifiers rect.
It depends on what you're doing and what you have available.
If you can find a good center tapped transformer with the target voltage, that will save you 2 diodes.
If you're going for the "quick and dirty" solution and you don't have a center tapped transformer, a bridge rectifier is an excellent way to get dirty DC.
It is a model for the equivalent circuit of a Transistor.
What is the current in a 12volt circuit that has 9 ohms of resistance?
Ohm's Law: Current equals voltage divided by resistance
If the two 3 ohm resistors are in series, then 12 volts divided by 6 ohms is 2 amperes.
If the two 3 ohm resistors are in parallel, then 12 volts divided by 1.5 ohms is 8 amperes.
WARNING: In the first case, this is 24 watts or 12 watts per resistor. In the second case, this is 96 watts or 48 watts per resistor. Exercise great care if you intend to duplicate this in the lab, i.e. do not think for even a split second that a 1/4 watt resistor is going to be able to handle this power without burning up and causing a fire.
How does schmitt trigger differ from bistable multivibrator?
Schmitt trigger refers to an input hysteresis mechanism to improve the noise tolerance of a digital input, preventing glitch generation or false triggering on outputs.
A bistable multivibrator is a flipflop, a device capable of storing one bit.
What are the advantages of raster scanning?
Image file formats are standardized means of organizing and storing images. Image files are composed of either pixel or vector (geometric) data that are rasterized to pixels when displayed (with few exceptions) in a vector graphic display.
The most important characteristics of an image stored in as a file are:
- size in bytes (depends on image resolution and on the compression techniques)
- color space (RGB, HSI, supporting transparency)
- color depth (how many colors for a single pixel can be represented)
- support for multiple images in a file (additionally animation can be supported)
- number of dimensions supported (2D images, 3Dimages)
The various image file formats try to optimize some of these parameters. Depending on what you want to do with the image, you may need a small file or a very high color depth (like 16bit per color channel) or a small animated graphic or ... For each of these tasks there is one or more image file formats that are better suited. Below are listed the most common advantages and use cases for the best known raster image formats.
If you want to convert between formats, please see the second linked article (How do you change a photo resolution or image format?)
The JPEG/EXIF file format is optimized for storing photographs like images. It uses lossy compression, RGB, 8 bit per channel, no support for transparency or multiple images, 2D images support. The files are small and as long as the compression is not too great the image quality is almost identical to the original. JPEG images are very common, being supported virtually by every imaging device and image processing software. Due to their small size are ideal for storing, transmitting and embedding photos or similar images.
The GIF file format is optimized for small, lower quality images. It uses a lossless compression, palette based with a maximum of 256 colors, supports transparency and multiple images and animation, 2D only. This makes the GIF format suitable for storing graphics with relatively few colors such as simple diagrams, shapes, logos and cartoon style images. It is still widely used to provide image animation effects.
The PNG file format was created as the free, open-source successor to the GIF. It supports additionally to GIF RGB images with 8 bit per channel. It does not support multiple images and animation. The PNG format is widely used on the WEB due to transparency and lossless compression.
The BMP file format is a simple format used to store images like bitmaps. It is widely supported by the operating systems. It supports some simple lossless compression, can be either palette or up to RGB32 based, supports transparency, only 2D images. Due to the large image file and the availability of better formats like PNG, TIFF its use remains mostly restricted to the OS scope or as a temporary format when exchanging images.
The TIFF is a flexible format that can represent everything from fax images to photos compressed or uncompressed as a bitmap, including additional image information like EXIF. TIFF supports up to 16bit per channel, transparency, multiple images, 2D images in multiple planes. It is widely used by scanners and fax machines due to its support for all possible color depths and multiple images (for example the pages that are scanned/faxed). It gets also used in digital cameras as a lossless format.
The RAW image format, sometimes called digital negative, contains minimally processed data from the image sensor of either a digital camera, image or motion picture film scanner. It is typically uncompressed or minimally lossless compressed, supports up to 16bit per channel, no transparency. Multiple images are in several variants of the format supported. There are hundreds of raw image formats in use by different models of digital equipment (like cameras or film scanners).
Why are fixed resistors printed with color bands rather than numeric values?
Resistors can be quite small and most are cylindrical. The printing would be quite small and not only hard to read, but also hard to print a fine text onto them.
Having said that, some old Russian equipment does have the value printed on the resistors.
So, it is easier, cheaper and simpler, to use a colour coded banding system.
What the role of a resistor in an led circuit?
a resister is to RESIST current flow....if the LED gets the full effect of the power supply, the LED will immediately blow out.
Who performed an experiment with cathode ray tubes?
J. J. Thomson
J. J. Thomson did the cathode ray experiment where he discovered the existence of electrons.
What are the three main function of the multimeter?
A typical multimeter can measure:
* AC & DC voltage (volt)
* AC & DC current (amp) * resistance (ohm)
Is nand gate a universal gate?
NAND AND NOR gates are called universal gates , becaus with a combination NAND and NOR gates alone, it's possible to create all other logic gates like AND, OR, XOR etc and you can design any logic circuit. eg: inverter-- nand with inputs shorted.
and ------ nand followed by a inverter(using nand).
or--------- giving inverted inputs to nand gate.
What is the input impedance of an ideal voltage op-amp?
To get all the voltage from a source to a target without loss you need voltage bridging, that is a relative low output impedance to a higher input impedance. Usualy the input impedance is more than ten times higher then the output impedance.
An input impedance is called also a load impedance or an external impedance.
An output impedance is called also a source impedance or an internal impedance.
What is the peak value of a 115V rms sin wave?
RMS*SQRT(2)=V(peak)
or
115V*1.414= 162.63V(peak)
Source: What_is_the_conversion_for_rms_voltage_to_peak_to_peak_voltage
