0
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 public switched telephone network?
PSTN (public switched telephone network) is the world's collection of interconnected voice-oriented public telephone networks, both commercial and government-owned. It's also referred to as the Plain Old Telephone Service (POTS). It's the aggregation of circuit-switching telephone networks that has evolved from the days of Alexander Graham Bell ("Doctor Watson, come here!"). Today, it is almost entirely digital in technology except for the final link from the central (local) telephone office to the user.
In relation to the Internet, the PSTN actually furnishes much of the Internet's long-distance infrastructure.
A domestic telecommunications network usually accessed by telephones, key telephone systems, private branch exchange trunks, and data arrangements.
Ø In North America, you have access to the Public Switched Telephone System (PSTN). The term PSTN used to refer to the public communication system that provides local, extended local and long distance telephone service to the majority of the United States and North America. This system is made available to the public through a group of common communications carriers such as American and Canadian phone companies who have agreed to exchange calls and connections on behalf of their subscribers as mandated by international law and the laws of the country in which they do business and and provide telephone service. Anyone who subscribes to this public service may make calls to anyone else who has purchased access to the phone system through any other carrier.
Routing calls requires multiple switching offices. The phone number itself is a coded map for routing the call. In the United States, for example, we have 10-digit phone numbers.
- The first three digits are the area code or national destination code (NDC), which helps route the call to the right regional switching station.
- The next three digits are the exchange, which represents the smallest amount of circuits that can be bundled on the same switch. In other words, when you make a call to another user in your same exchange -- maybe a neighbor around the corner -- the call doesn't have to be routed onto another switch.
- The last four digits of the phone number represent the subscriber number, which is tied to your specific address and phone lines.
Within a company or larger organization, each employee or department might have its own extension. Extensions from the main phone number are routed through something called a private branch exchange (PBX) that operates on the premises.
To make an international call requires further instructions. The call needs to be routed through your long-distance phone carrier to another country's long-distance phone carrier. To signal such a switch, you have to dial two separate numbers, your country's exit code (or international access code) and the corresponding country code of the place you're calling.
Almost all exit codes are either 00 or 011, although there are a few exceptions like Cuba (119) and Nigeria (009). Country codes are one- to three-digit prefixes that are assigned to specific countries or groups of countries. For example, the country code for the United States is 1, but the United States shares that country code with Canada and several smaller island nations like Jamaica, Puerto Rico and Guam. The country code for Mexico is 52 and Saudi Arabia is 966. Here's a full list of exit and country codes.
What is dangerous limit of voltage for 50Hz AC current for adult?
The danger level is dependent on the individual, and the individuals environment. You need to understand the danger of electricity is due to the fact that our bodies operate on electrical impulses. When electrical impulses are induced into your body by forces outside your body that override your brain's signals, bad things begin to happen. The number 1 factor that determines what force (ie voltage) is necessary to "inject" electricity into your body is the resistance of your epidermis. This resistance is impacted by dryness, fat content, stress levels, the presents of salts and other minerals, and a host of other things.
Current flowing through your body in excess of ~20mA at 50Hz can be dangerous. Your body's resistance is likely to be somewhere between 1000 and 500000 ohms. Using ohm's law, as little as 20 volts could, under the right conditions, be dangerous. That is why you should always treat electricity with respect - Don't turn on/off lights with soaking wet hands; don't use electronics plugged into a wall socket in a bathtub, turn off the circuit breaker if you are doing any home wiring that impacts that circuit, etc.
By "Dangerous", I'm referring to the let go current levels. These are the current levels where you no longer have control of whatever part of your body has completed the circuit. At these levels, the signals from your brain are too small relative to the outside influence to tell your muscles to do anything. That's why it's called the let go threshold - you can't let go anymore! As little as 50 volts can cause ventricular fibrillation/death in a matter of minutes.
What are the different types of register?
There are two type of register in computer cpu. first one is data register and second one is address register.
How are magnetic field lines arranged?
Magnetic field lines spread out from one pole, curve around the magnet, and return to the other pole.
. . ah, they don't actually spread out from the poles, inside the magnet they are bunched together but they still form closed loops with the lines outside.
Why do distant objects ripple on a hot day?
Distance objects can be seen to "ripple" on a hot day because of refraction. As light from a distance object makes the trip to the observer, it passes through air of slightly varying densities. This causes it to "change course" to a degree, which is refraction. It is this thermally induced refraction that is responsible for the "ripple" we see, and for the mirage we sometimes hear about.
Describe how an hollow cathode lamp work?
The typical hollow cathode lamp consists mainly of a cathode containing the element of interest, an anode, and an inert gas. After application of a potential difference between the cathode and the anode, the gas will accelerate toward the cathode removing its material; a process called sputtering. The element of interest is now in the excited state, and upon its return to the initial non-excited state, it would emit light waves of specific wavelength, that can be studied later.
first create truth table, inputs should be combination of 3 bits i.e 8 possible combination. the outputs are the square of each input. you need 6 bits for the outputs since the square of 7 is 49 which is binary notation 49 is (110001) hence 6 bits. same goes for the other inputs. when the table is complete. find the Boolean function that drives each bit, preferably by K-maps to minimize the logic. Then from the equations, simply draw the circuit by using the necessary logic gates. There will be 3 inputs and 6 outputs for the overall circuit.
Very easy but tedious. have fun
When It is required to calculate average voltage and when RMS voltage?
It is usually required in electrical examinations to make calculations. Simple answer to a complicated calculation. Remember, take peak to peak voltage and multiply by .707, the result being average voltage. This is the voltage that electrical test meters read.
How do you interface grid with inverters?
Yes, it is obviously possible to join together power lines from separate generators. All power grids depend on this. However, unless they are brought into phase carefully, then disaster awaits.
Once connected together, the two systems should remain in phase, provided the response times of the systems are suitable.
In detail, what is happening is that if our generator attempts to lead the phase of the combined system, then it will take more of the system load, and will then slow down slightly, thus bringing it back into phase. Inversely, when our generator slows slightly, it will shed load, and speed up again.
But any grid is subject to momentary imperfections of waveform and phase, and the connecting system must be able to deal with that.
Expert advice should be sought as to the detail of how to do this.
What is the piv for diode if input is 50v?
The PIV (Peak Inverse Voltage) for a diode is the maximum reverse voltage that the diode can withstand without breaking down. If the input voltage is 50V, the PIV should typically be greater than 50V to ensure safe operation under reverse conditions. It's common practice to choose a diode with a PIV rating at least 20-30% higher than the input voltage, so a diode rated for at least 65-70V would be advisable.
What is the difference between voice simulation and voice synthesis?
Voice synthesis is a process for creating sound from another media, e.g., written text. Voice simulation is a process for creating sounds that mimic some specific persons voice. Simulated sounds may or may not be synthesized.
What is the relationship between acceleration and distance?
displacement (s)=initial velosity(u)*time(t) + 1/2 acceleration (a)*(t^2) from a stationary start this simplifies to s=1/2a(t^2) this arises from the fact that a is the second integral of s with respect to time eg. d/dt=s: x=st+u (velosity v=distance*time +initial velosity) (d^2)/d(t^2)= s(t^2)/2+ut+d=a as we are measuring displacement and not position, the constant of integration d drops, leaving a=s(t^2)/2+ut : s=ut+1/2a(t^2)
What is the definition of instrumentation impulse line?
The impulse line is the piping or tubing used to connect the transmitter to the process. To ensure correct readings, it is essential that impulse lines be installed correctly for the type of fluid that you are measuring. Consult your transmitter installation manual.
What is the use of filter circuits?
A filter circuit is an electronic circuit made using capacitors and inductors. It is designed to produce a restriction on the frequency-bandwidth of an alternating input signal - such as, for example, a wireless/radio signal - to produce a narrower frequency- bandwidth as its output.
Another common use of an electronic filter circuit is to remove most of the ac ripple which remains in the output of a diode-based ac rectification circuit so that the resulting is of better quality.
What is the function of registers in a micro controller?
Well , the register in micro processors or controllers is memory place that will save the values to be executed , for example if i want to add two numbers in 8085 i would first save ( or write ) the the first parameter into register "A" by applying this command "MVI A,80H" then i would write my second parameter into register "B" by applying "MVI B,20H" , now i can add ( sum ) them together bu using this command "ADD B" . the register "A" will have the result which is "A0".
As you can see to make any operation i should save ( or write) the values into register then i will execute command on them .
Good Luck !
Can you trace the location of your Metro PCS phone?
To the best of my knowledge, you most likely would not be able to do this.
In order to actually locate the GPS coordinates of your handset without having it in your possession, you would need to have first installed a program on your phone that would allow you some sort of remote access to it's GPS information, and your phone would need to have a GPS chip available for you to use... like in some model blackberry phones or high end smart phones.
KLM was founded on 7 Oct 1919 by Albert Plesman, making it the oldest carrier in the world still operating under its original name, though the company stopped operating during the Second World War - apart from the operations in the Dutch Antilles in the Caribbean. The first KLM flight was on 17 May 1920, from Croydon Airport, London to Amsterdam carrying two British journalists and a number of newspapers.
