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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 telecom engineering and electrical engineeribg?
i dont knw the answer thats why m asking from u stupid people
The influence of a coil of wire upon an alternating current passing through it, tending to choke or diminish the current, or the similar influence of a condenser; inductive resistance. Reactance is measured in ohms. The reactance of a circuit is equal to the component of the impressed electro-motive force at right angles to the current divided by the current, that is, the component of the impedance due to the self-inductance or capacity of the circuit.
What is an maskable intErrupt?
interrupts in 8085 are basically classified into two types:
1.Maskable
2.Non maskable
maskable interrupts are those which can be delayed.This is done by masking off the interrupts which are not required.
Maskable interrupts are:RST 7.5,RST 6.5,RST 5.5 and INTR
<decreasing order of priority>
Why using 555 timer in ir transmitter?
The 555 is a timer and oscillator chip capable of sourcing and sinking 200 milliamperes, and is useful for pulsing an infrared LED to power an infrared transmitter. It can be pulse width modulated or otherwise controlled via the various control pins.
See: http://talkingelectronics.com/FreeProjects/555/555-P3.html
in most cases the IR detector used is TSOP sensors which works only on a specified frequency of 38KHz. So by using 555 timer, we can design the circuit very easly to work @ 38KHz. dats why in 555 is used in many IR txns.
How do you measure amplitude of a ripple?
Most true RMS voltmeters can measure the value of a ripple voltage on top of a DC supply, when you place it in AC mode. You can also place a small capacitor in series with a DC voltmeter and that would measure the ripple. The real way to do this, because ripple voltage is not sinusoidal, is to use an oscilloscope, particularly if you want the peak values.
How is current measured in a series circuit?
Current is measured in a series circuit by the use of a multimeter. First, the power source must be attached to the circuit board. The board is attached to the multimeter, then that is attached back to the power source.
AnswerCurrent is measured either with an ammeter, or with a multimeter set to measure current. The instrument must be connected in series with the other components in the circuit.
What are the advantages and disadvantages of phase modulation?
Advantage - 1. Phase modulation & demodulation is easy compared to Frequency modulation. 2. Phase modulator is used in determining velocity of moving target by extracting Doppler information. Doppler information needs stable carrier which is possible in phase modulation but not in frequency modulation. Disadvantage - 1. Phase ambiguity comes if we exceed its modulation index pi radian(180 degree). 2. we need frequency multiplier to increase phase modulation index.
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Apex- 12 ((:
How a zener diode can be used as a voltage regulator?
A: A zener diode is manufacture to reverse breakdown at a certain voltage this voltage will remain almost constant no matter how much more voltage is available [within operating parameters]. this zener must be able to sustain both itself operating currents plus the load
What is an analog and digital control system?
http://wiki.answers.com/Q/What_is_an_analog_and_digital_control_system"
Can current flow in a circuit without potential difference?
A current cannot exist without voltage but voltage can exist without current.Simple example is battery. A battery has votlage even though it is not connected elsewhere.
The output frequency of the half-wave rectifier will be 60 Hz if the input is a 60 Hz sine wave.
One cycle of the input will include the positive going and the negative going portions of the sine wave. The output will have either the positive going or negative going half of the input wave, and will have no output during the other half of the input sine wave when the diode is reverse biased. What that output will look like on an oscilloscope is half a wave and then a "flat spot" where there is no output (owing to the diode being reversed biased). Let's keep going.
The frequency of a signal is the number of cycles of the signal per second. Further, we know that in a waveform, one cycle occurs when the wave goes through all of the changes it must go through to, shall we say, get back to where it started. In the half-wave output, the signal goes through half of the input wave, and then the voltage sits at zero. That means that one output cycle consists of that voltage excursion, and that period during which the diode is back biased. So the time for one complete cycle of the output is the same as the time for one complete cycle of the input. Thus, a 60 Hz input signal (that sine wave) will give us a half-wave rectified 60 Hz output signal.
How does an electret microphone work?
The electret microphone is based on the electret capacitor, which is a special capacitor with quasi-permanent charge. Vibrations in the air are picked up by the capacitor, which generates an equivalent vibrating electrical signal. Unlike a traditional condensor (another name for capacitor) microphone, the electret does not require a power source.
Advantage and disadvantage of multiprocessor?
A food processor is a multifunctional kitchen appliance that is designed to quickly and easily perform repetitive food preparation tasks like chopping, slicing, shredding, grinding, and pureeing. A food processor can be used to prepare almost any type of food. Importantly, a food processor can be a valuable time saving resource for any cook and eliminate stress that would otherwise be put on hands, wrists and forearms from repetitive cutting tasks.
the disadvantages are;
· They're usually really noisy
· They're hard to clean
· They might over cut, blend, chop, grate, need
· You don't have much control
· If you forget the lid to the tube it could go everywhere
· They are very dangerous to clean because of the sharp blades
What is the function of a conductor?
It means do you want a mansion a jacuzzi to watch your movie the goonie loonies then we start bubling then what you doing next week ohh ohhh im the olny one you need now oh now just a mofuking kids oghh
What is the function of ic 741 op amp?
The LM741 series are general purpose operational amplifiers which feature improved performance over industry standards like the LM709. They are direct, plug-in replacements for the 709C, LM201, MC1439 and 748 in most applications. The amplifiers offer many features which make their application nearly foolproof: overload protection on the input and output, no latch-up when the common mode range is exceeded, as well as freedom from oscillations. The LM741C is identical to the LM741/LM741A except that the LM741C has their performance guaranteed over a 0°C to +70°C temperature range, instead of -55°C to +125°C.
What is the Working principle of proximity sensor?
there are different types of proximity sensors namely inductive capacitance and infrared. the working principle of inductive proximity sensor is,
it consists coil, oscillator, detector and trigger circuit. when current flows through a coil magnetic field will be generated and when the metal get contact with that field
the voltage is induced in the metal the detector detects this loss in voltage and triggering circuit will give the contact output...
praveen achalkar
MCF mangalore
What are Disadvantages of digital control?
Unwanted Errors of precision when the analog signal is converted into a quantized, sampled digital signal. The same error arises when the digital signal is then converted into an analog signal for the plant to use.
Why the secondary of the current transformer should not be open circuited?
The secondary of a CT must always have a load connected. An open circuit secondary can result in the development of a dangerously high secondary voltage. If a CT is energized but is not used, the output terminals of the CT must be shorted out.
first you need a analog multimeter. put in your meter in the ohm section x10. then remove the cap in the ckt and discharge that. then connect the multimeter -ve probe to the cap +ve terminal and connect the other terminals.the needle comes to low value then com to infinity, remove the probs then connect multimeters -ve prob to the cap -ve terminal that time look carefully the meter's needle comes to the one value and go back to the infinity that the low value is capacitors equivalent resistance value. the cap is 1000uf the equivalent resistance value is around 15 at x10 .the cap is 100uf the equivalent resistance value is around 15 at x100
It might be helpful to have a working definition of modulation before making a statement as to why it is needed. In fact, with an understanding of what modulation is, it will be obvious why it is included in electronic communications.
Modulation is the "message" or the "intelligence" that is impressed on a radio frequency (RF) carrier. When we transmit a signal, we generate a carrier frequency, and then we modulate it. We "add" the message or the information we wish to transmit by modulating the carrier in some way. There are at least a dozen different modulation schemes ranging from simple to real head scratchers. They either modify the amplitude, the frequency or the phase of the carrier. Let's look at a few.
The simplest modulation technique is taking the transmitted signal and turning it on and off. It is "keyed" to send a series of pulses. Morse code uses on-off keying. In this method of modulation, no modification of the RF carrier signal itself is made. It is simply switched on and off. (It could be looked at as amplitude modulation with the carrier either at zero amplitude or at "maximum" amplitude with nothing in between.) A series of pulses can be transmitted. With Morse code, a short "on" period will send a dot or "dit" out. If we extend the "on" period a bit, we can send a dash or "dah" out. Nothing real sophisticated here, but basic and effective communication. There are obvious limits to how fast information can be transmitted with this modulation scheme. (But don't tell the hams who still use it!)
Most of us are familiar with AM radio. AM is amplitude modulation. The amplitude of the RF carrier is modified to modulate it. The amplitude of the modulating signal will determine the amount that the amplitude of the carrier is changed. (The volume of the modulation determines how much the amplitude of the carrier is changed. The frequency of the modulating signal determines the rate of change of the amplitude of the carrier. (The frequency of the modulation determines how fast the amplitude of the carrier is changed.). The frequency of the carrier is held constant through all this.
How about FM? In frequency modulation, the amplitude of the carrier is constant. It's left alone. But the frequency of the RF carrier is changed. It is swung above and below where it sits (it's assigned center frequency) at a rate proportional to the frequency of the modulating signal, and at an amount proportional to the amplitude of the modulating signal. In FM single sideband, the carrier frequency and the frequencies above the carrier are transmitted and the frequencies below the carrier are suppressed (upper sideband transmission). Or the frequencies below the carrier are transmitted with the carrier and the upper frequencies are suppressed (lower sideband transmission). In conventional television, the video signal is single sideband, suppressed carrier. It's like "regular" upper sideband transmission except the carrier signal is suppressed. Sideband transmission "saves" space on the RF spectrum. And it works because we really don't need "all" of the FM signal to demodulate the signal at the receiver.
Other forms of modulation become more complex. CDMA (code division multiple access), TDMA (time division multiple access) and other methods are used in cell phones to modulate the carrier so the digital data stream can be impressed on the carrier.
Modulation is the addition of intelligence to a carrier signal. It's the message. Modulation is necessary because the point of communication is getting the message through.
A Simple answer:
Simply this... Any communications medium: e.g. Free space - radio waves, Air - Sound waves or radio waves, Optical Fibre - Light, Copper Wires Electrical Anergy (with frequency limits of the copper wire construction) is made for a certain type of signal. But if the signal we want to send is not compatible with the medium, then it does not travel well.
Modulation changes the information we want to send from it's original form, into one that is more compatable with the medium we are trying to use.
For example, your computer speaks digital over a TCP/IP LAN which requires CAT 5 or better rated cables,, but to connect to your internet service provider (ISP), you need to send the signal over the wires of the telephone company (made for voice tones). To make this connection, and ADSL modem (modulator/demodulator) is used to convert the data into audio tones, which pass over the telephone line, and at the far end are converted back to digital to join the service providers network. in the reverse direct the ISP does the same, and the signals are de-modulated, back to data for your network.
Or in simple terms, Its about best use of the medium. Everything else is just a away of doing it. And there are a lot of possible ways to choose.
What is PLC programming and who uses it?
PLC stands for "programmable logic controller". PLC's are usually used to control machinery in automated processes such as manufacturing. PLC programmers usually complete a trade school certificate before starting their careers.
Advantages and disadvantages of time division multiplexing?
Advantages of TDMA
1. The user gets full bandwidth of the channel in a particuler time slot.
2. For bursty signals such as voice or speech TDMA gives maximum utilization of the channel
3. most suitable technique for digital transmission.
Disadvantages of TDMA
1. it is not much suitable for continues signals
2. extra guard time are necessary
3. synchronization is necessary.
