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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 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
Direct Current (DC) is an electric current flowing in one direction only.
For the source and more detailed information concerning this subject, click on the related links section indicated below.
What are the disadvantages of emitter follower?
Emitter bias provides excellent bias stability in spite of changes in or temperature. It uses
both a positive and a negative supply voltage. To obtain a reasonable estimate of the key dc.
Shamsulhuda(shams) Afghanistan
How do you short the capacitor?
There is no resistance between cathode and anode when measured with a multimeter. You can also lick the terminals. If charged, it'll taste much like the terminals of a 9v battery, which, interestingly, tastes much like going down on a girl.
Square wave is analog or digital signal?
This question has become the point of much heated debate here on WikiAnswers, and I will attempt to pare down the answers to its simplest form while keeping all valid viewpoints intact. Any further debate should be put in the "Discussion" area.
The Case For Digital: With a few exceptions, a square wave in it's theoretical form will most likely be used in digital applications.
A square wave may be "analog" during the time it is in transition from one stable state to another, and "digital" when it is in one state or the opposite state (i.e., voltage level), according to the type of digital inputs stimulated, but a transition is not an analog state function in the context of computers or digital logic. A square wave has two states hi and low and the transition from hi to low can be switched up to gigahertz (GHz) frequencies. Test equipment manufacturers are able to generate square wave signals well above 100GHz. Function generators have the square wave signal where the transition can be controlled. Practically all digital circuits utilize these states as "1" and "0" (or true and false) that computers use to make decision at the machine language level. Furthermore all modern computer uses this signalling scheme. But digital signals (1's and 0's) are not necessarily "square" waves, strictly speaking. A clock circuit generates a square wave that is used as a timing reference for the address, data, and control circuits.
The Case For Analog: All theoretical waveforms look great on paper, but it is impossible to produce any perfect waveform. Therefore, all waveforms (including square waves) are inherently analog.
By Fourier Analysis, a square wave is actually an infinite series of the summation of sine waves, in this case the odd harmonics divided by N. As a result, a square wave can actually be considered an analog signal. Looking at this another way, no pulse driver, conductor, or transmission line is perfect, so the rise and fall time of a square wave are not instantaneous, meaning that the series is not really infinite so, again, the square wave is analog, although quite complicated, but still analog. We call it digital because we sense it with discriminators that decide the "value" of the wave based on some thresholds with appropriate hysteresis.
The Case For Sanity: A wave form is not inherently digital or analog. "Digital" and "analog" are arbitrary words used to describe an application of waveforms. In other words, all digital signals are square waves, but not all square waves are digital.
A square wave is usually used in digital applications, but is also used in audio applications for a "distorted" guitar or vocal effect. A sine wave can become a square wave if the input signal on an amplifier is too great for the power of the circuit to amplify, "clipping" the high and low portions of the sine wave.
A square wave can be considered an analog or a digital signal. A perfect square wave (not possible to generate based on Fourier Analysis) would not in general be considered an analog signal because it only has two values, defeating the point of analog (in many cases, but not all). One can make a square wave oscillator to use as an alarm - different frequencies were used to convey different information. A square wave was simple to create, thus my reason for using as opposed to a sine wave (this is an example of an analog use of square waves - the information is not stored in the two values of the wave, but in the "infinite frequency range made available by the extra circuitry to change frequencies."
This point is moot, really, because it is the nature of the data (being analog or digital) that truly is important, and defines whether the wave should be catagorized as "analog" or "digital".
Oh-So-Clever Analogy: A wrench is the perfect tool for fixing trucks, but if I use the wrench to fix a desk, that doesn't make the desk a truck. In short, the application defines the state, but does not limit the tool.
Describe the purpose of a resistor in a circuit?
Resistance:
Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must be dropped (used) across the conductor (wire). Resistance can be described by ohms law:
Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms)
where:
Voltage [V]= the energy lost across an component (voltage measured in volts).
Current [I] = the charge (electrons) flowing through an component (current measured in Amps).
Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your hand steady.
When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen that electrical resistance plays a large role in modern life.
Resistor:
The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependent on the amount of power passing through the resistor, given by:
P = V x I (Power = Voltage x Current) (power measured in watts)
There are also many types of resistors including:
· Variable Resistor - changes resistance when its shaft is rotated (volume knob on a stereo).
· Thermistor - changes resistance when the temperature changes (used in a thermostat).
· Light Dependant Resistor (LDR) - changes resistance when the lighting changes (used in children's night-lights).
Resistor Example:
An LED is a small red light (such as the one on the front of most TVs) and requires 2.0 volts and 0.02 amps to operate correctly. If we connected that LED up directly to a 12 volt battery, the voltage would be too high, and too much current would flow… the LED would blow up. We need to use a resistor to limit the voltage and current.
But which value of resistance should the have resistor? Uses ohms law:
R = V / I = (12.0 - 2.0) / 0.02 = 500 ohms
(Note: the voltage across the resistor is the battery voltage minus the voltage we want across the LED)
But which value of power should the resistor be capable of handling?
P = V x I = (12.0 - 2.0) * 0.02 = 0.2 Watts
Why resistance is connected in series with P-N junction diode?
A resistance is connected in series with p-n junction of diodes to limit the number of electrons that flow across the junction.
Why does slope overload occur in delta modulation?
To reduce slope overload distortion ,the step size must be increased when the slope of the input signal is high.
The sawtooth is better able to
match the message in the regions of steep slope.
What is the positive terminal of a diode known as?
It is called the positive + terminal or post, just like you list. Electrons flow for the negative - to the + terminal contrary to popular belief.
Another Answer
As electrons flow through the external circuit from anode (negative terminal) to the cathode (positive terminal) , then the answer is 'cathode'.
What is the unit for modulation index?
Modulation index is also called as Modulation depth. The modulation index of a modulation scheme describes by how much the modulated variable of the carrier signal varies around its unmodulated level.
How can Propagation delay be avoided in a parallel adder?
The parallel adder which we use in the digital circuits ,the carry output of each full adder stage is connected to the carry input of the next higher order stage.therefore,the sum and carry outputs of any stage cannot be produced until the input carry occurs;
This leads to a time delay in the addition process.This delay is known as carry propagation delay.
to the second question the propagation delay can be avoided in the binary parallel adder with the help of look ahead carry generator
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How are microwaves transmitted?
Microwaves are electromagnetic radiation. They are electromagnetic waves, and they are transmitted like light or radio waves, both of which are forms of electromagnetic radiation. The radiation leaves the microwave source in waves, and this radiation will travel effortlessly through a vacuum, and with a bit of loss through air.
What are some examples of technology?
food
chemical and petroleum
textile industry
transportation industry
Most of the new TV's display a blue screen when there's no signal for it to lock on. Try unplugging it for about 5-10 minutes and see if that clears up the problem. Why? Because they have microprocessors in 'em (computer chips) and just as like with any other operating system, they can hang up or crash. This isn't an uncommon problem with today's TV sets. Unplugging it for awhile resets the microprocessor (in other words, it causes it to re-boot when you plugit in again).
Can you charge a 9 volt battery with a 12 volt charger?
no, there is a high probability that it will explode
What is the practical use of astable multivibrator?
it can be used any where, where we need the clock pulse train of low frequancy.
like a function generator contains.
astable multivibrator is used to produce waveforms
as Astable means the circuit is not set to one state or the other but rather oscillates between those states. Therefore the application is signal generation
