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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 need of scaling in digital signal processing?
saturation arithmetic eliminates limit cycle due to overflow, but it causes undesirable signal distortion due to the non linearity of the clipper.In order to limit the amount of non linear distortion , it is important to scale the input signal and the unit sample response between the input and any internal summing node in the system such that overflow becomes a rare event.
What instrument measures current and voltage?
Voltmeter.
Current and voltage are two different things. They are closely related but a current does not imply a voltage and nor does a voltage imply a current.
A volt meter is used to measure a voltage. The voltage may be across a battery or other power source. It may be across a component such as a resistor or a group of components. If a current is flowing through a resistor, there will be a voltage across the resistor. Similarly, if there is a voltage across a resistor, there will be a current flowing.
Current is measured using an ammeter - Current is measured in amps, hence the name of the meter.
The two meters together can be used to analyze most electronic circuits and they are the two most important items of test equipment in electronics. Devices called multi-meters are combined ammeters and voltmeters and are in every electronics engineer's toolbox.
How do you calculate the forward resistance of a diode?
FIrst of all, figure out where your anode and cathode is, then take the cathode, connect it to the ground, in this case youre anus. And then take the anode, and connect it to the positive, again, in this case, your clitoris or penis (depends on your gender) then take a Digitial Multi Meter, and connect the positive in your left nostril, and take the negative and connect it to youre right nostril. If you feel aroused, then you are connected properly, if you feel depressed, youre connections are wrong.
Formula:
X(constant) = 1
Forward Resistance= 2+2-x-x(pubes)
What is meant by bidirectional power flow?
I guess it means that in your system, you can make the input output and vice versa. Example, if you have power conditioning unit (PCU) that either operates as rectifier or inverter. That means your PCU has bidirectional power flow. you can then operate it on the mode you need; rectification or inversiion mode.
I hope that was helpfull
Naeem, Mohammad
What is range of wire wound resistors?
There is no set range for these types of resistors. The biggest thing to keep in mind is the heat that is generated by the resistance and the applied voltage. The device should be large enough to dissipate this heat.
Why current is reduced if another resistor is connected in series?
Lets start with a very old analogy. Electricity flows through wire like water flows through a pipe.
That should give you a way to see this, the resistor resists the flow of electricity like a partially closed tap slows down water going into the sink.
The first diode was the Galena Cats Whisker. It was invented shortly after the development of radio, but I'm not sure by who.
Fleming's vacuum tube diode came shortly afterwards.
Why does a cathode ray tube have low pressure inside?
Low pressure inside a cathode ray tube? How about nopressure inside the tube! In a cathode ray tube, the "cathode ray" is an electron beam that is used to paint a "picture" on the phosphor coating on the inside of the tube. (We look at the "picture" from the other side of the glass on which the coating is laid down - the outside.) An electron is a lightweight little dude. It weighs about 1/1836th as much as a single proton, so anything, any gas atoms that are in the flight path of an electron will cause it to scatter. That means we need to pump all the air out of the inside of the tube. After we remove all we can, we fire a "getter" (a chemical coated onto a small area inside the tube) which will bind any remaining gas molecules left inside the tube to complete the evacuation process. No more pesky atoms to get in the path of the electron beam and scatter it all over the place.
What is the difference between analog and digital electronics?
An anlogous signal represents a slowly varying quantity with respect to time . A sinusoidal souce is an example of an anlogue signal. The digital signal is one which has only two stable staes.Either On or OFF. During On full signal and during Off No signal. We can also think of Digital signal as the output of an amplifier with input over driven with an analogue signal. its ouput saturates and gives full DC ouput voltage when it is ON and gives zero ouput for OFF. Uma1976 An analog signal is a variable signal, where as a digital signal is simply on or off.
for example a video game steering wheel.
With analog you can turn slightly anywhere between 0-90 degrees.
With digital you can ONLY turn 90 degree's or 0 degrees'.
This also works with buttons. Analog buttons can calculate how hard they are being pressed. Digital buttons only register if they are on, or off.
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Analog electronics receive, process or output analog signals. Digital electronics receive, process or output digital signals.
An analog signal is infinitely variable (usually between some limits). Its value could be 3, 3.2, 3.25, 3.257, 3.2573, etc. The signal "flows" from one value to another passing through the infinite number of values in between. For example a sine wave.
A digital signal has discreet values. There are usually a finite number of possible values. The signal has steps instead of a smooth flow. For example, it might have a value of 3 or 4, but there is no such thing as a value of 3.5. Using a step analogy, you can stand on the 3rd step of a stair case, or the 4th step, but you can't stand on the 3.5th stair - it just doesn't exist.
Note that either type of signal can be made to approximate the other, usually to any level of accuracy that is necessary.
Also note, because many digital signals are binary (either on or off, 1 or 0), the terms digital and binary are sometimes confused. A digital signal can have more than two states, so not all digital signals are binary. But, all binary signals are digital. That is, binary signals are a subset of digital signals. ANALOG is not ONLY sinusoidal but it can be DC direct current. Consequently a limitless variably information. Is it better then digital NO WAY at very small quantity the noise is ambiguous as signal while digital has only 2 states true or false.
What is amplitude demodulator?
(I am assuming you want to know what an "AM Demodulator" is, as follows) AM stands for Amplitude Modulation, perhaps the most basic kind of modulation of a radio carrier wave. Information, typically voice or music, is impressed on a radio carrier by simply varying the strength or 'amplitude' of the carrier (which is ordinarily at a much higher frequency than the information signal) versus time. An AM Demodulator, then, is a device which recovers the original signal, that is the voice or music, from the modulated carrier wave after it has been transmitted from the source to the receiver (which typically filters and amplifies the received signal before it is applied to the demodulator). The simplest AM Demodulator is a simple "diode", a 2 terminal semiconductor (or vacuum tube) device which, together with another filter, can convert the AM modulated carrier directly into the original form, discarding the carrier wave in the process. This is known as an "Envelope Detector". Other types of AM Demodulators exist, principally the "Product Detector". See the subtopic "AM Radio" in the Wikipedia entry for "Demodulation" for a little more information (it's not overly technical).
Explain free electron concept and electric current?
the flow of electrons in semi conductor is called electric current.
the electrons revolved around the nucleas is called free electrons
An uncharged capacitor acts like a short circuit when voltage is first applied to it?
Yes it does. Capacitors and capacitor banks have a high inrush current when first energized. As an example this is the reason that VFD's place a resistor in series with the capacitors for a short period of time when they are first energized to prevent damage to the rectification componente. They call it a precharge circuit. Current leads voltage by 90 deg in a purely capacitive circuit.
What is Grounding and shielding in electronics instrument?
in an electric circuit, it is treated as a reference from which other voltages can be measured. also it acts as a common return path of electric current leakages
How to Reverse the direction of a stepper motor?
Suppose if u r using four pole stepper motor. keep the first coil on then energize second coil. and then again energise the first coil instead third coil. you will get reversed now.. all the best
How many circuits can you have with 100A service?
As many as you want without exceeding the 100amps. You could have 100 circuits if all you have is a single 100watt light on each circuit.
What is the difference in the lower end of a 1982 GM motor and a 1996 GM motor?
1 piece rear main seal and the mounting location for the fuel pump is blocked off. May have bosses cast in lifter vally for hydrolic roller cam on the newer block
What will happen if instrument with 110v supply voltage give 220 v supply?
the appliance will burn out, eg if it is a 60 watt light bulb it will burn at 120 watt for as long as the fillament can take it and that wont be long
The 80% ideal is from the NEC. Let's say you have a standard 15A circuit. This circuit is rated to carry a maximum of 15A, no more. If you try to draw more than 15A, the breaker will pop. Now, you can put 15A worth of appliances on this circuit, but then you are running it at its maximum all the time. If you add anything else to this circuit, you will pop the breaker. If you have something that draws surge current, it can opo the breaker under normal use. You have no "wiggle room" when you load it at its maximum. Also, as touched on above, if you run your circuit at the maximum you cannot add anything else. This is generally a sign that you need to upgrade your wiring. Furthermore, the breaker can handle 15A indefinitly under standard test conditions, which are close to ideal. Your breaker box may not be ideal. Breakers are thermal devices, so self heating and heating from other breakers can be a problem. If your breaker is hot, it will pop sooner than if it is cold. The more current that flows through it, the hotter it will get. If you are overloading circuits the easiest thing to do is to break the circuit up into multiple circuits. The exact implementation will depend on the situation.
Explain construction and working of a Solar Cell?
How A Photovoltic Cell Works ----
Return Photovoltaics
The "photovoltaic effect" is the basic physical process through which a PV cell converts sunlight into electricity. Sunlight is composed of photons, or particles of solar energy. These photons contain various amounts of energy corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell, they may be reflected or absorbed, or they may pass right through. Only the absorbed photons generate electricity. When this happens, the energy of the photon is transferred to an electron in an atom of the cell (which is actually a semiconductor). With its newfound energy, the electron is able to escape from its normal position associated with that atom to become part of the current in an electrical circuit. By leaving this position, the electron causes a "hole" to form. Special electrical properties of the PV cell-a built-in electric field-provide the voltage needed to drive the current through an external load (such as a light bulb).
p-Types, n-Types, and the Electric Field
To induce the electric field within a PV cell, two separate semiconductors are sandwiched together. The "p" and "n" types of semiconductors correspond to "positive" and "negative" because of their abundance of holes or electrons (the extra electrons make an "n" type because an electron actually has a negative charge). Although both materials are electrically neutral, n-type silicon has excess electrons and p-type silicon has excess holes. Sandwiching these together creates a p/n junction at their interface, thereby creating an electric field. When the p-type and n-type semiconductors are sandwiched together, the excess electrons in the n-type material flow to the p-type, and the holes thereby vacated during this process flow to the n-type. (The concept of a hole moving is somewhat like looking at a bubble in a liquid. Although it's the liquid that is actually moving, it's easier to describe the motion of the bubble as it moves in the opposite direction.) Through this electron and hole flow, the two semiconductors act as a battery, creating an electric field at the surface where they meet (known as the "junction"). It's this field that causes the electrons to jump from the semiconductor out toward the surface and make them available for the electrical circuit. At this same time, the holes move in the opposite direction, toward the positive surface, where they await incoming electrons. Making n and p Material The most common way of making p-type or n-type silicon material is to add an element that has an extra electron or is lacking an electron. In silicon, we use a process called "doping." We'll use silicon as an example because crystalline silicon was the semiconductor material used in the earliest successful PV devices, it's still the most widely used PV material, and, although other PV materials and designs exploit the PV effect in slightly different ways, knowing how the effect works in crystalline silicon gives us a basic understanding of how it works in all devices. Absorption and Conduction In a PV cell, photons are absorbed in the p layer. It's very important to "tune" this layer to the properties of the incoming photons to absorb as many as possible and thereby free as many electrons as possible. Another challenge is to keep the electrons from meeting up with holes and "recombining" with them before they can escape the cell. To do this, we design the material so that the electrons are freed as close to the junction as possible, so that the electric field can help send them through the "conduction" layer (the n layer) and out into the electric circuit. By maximizing all these characteristics, we improve the conversion efficiency* of the PV cell.
To make an efficient solar cell, we try to maximize absorption, minimize reflection and recombination, and thereby maximize conduction. *The conversion efficiency of a PV cell is the proportion of sunlight energy that the cell converts to electrical energy. This is very important when discussing PV devices, because improving this efficiency is vital to making PV energy competitive with more traditional sources of energy (e.g., fossil fuels). Naturally, if one efficient solar panel can provide as much energy as two less-efficient panels, then the cost of that energy (not to mention the space required) will be reduced. For comparison, the earliest PV devices converted about 1%-2% of sunlight energy into electric energy. Today's PV devices convert 7%-17% of light energy into electric energy. Of course, the other side of the equation is the money it costs to manufacture the PV devices. This has been improved over the years as well. In fact, today's PV systems produce electricity at a fraction of the cost of early PV systems.
Why do you need to tin first the wire before soldering it?
pre tinning make it easier to solder wire because the solder is already " stuck" to the wire. and less solder will be needed to join the wire. if you watch the solder under a magnifier while tinning, you will notice the solder does not flow and "stick" until proper heat and flux ar applied. this heat usually is more than required to melt the solder because it takes mor heat to heat up the wire due to higher density. after tinning, less heat is required to melt the solder, and enough flux is usually left from tinning to quickly join the wire to the desired material provided the material is also tinned. this reduces cold solder and provides for a more relible connection. To tin the wire first is to cover the end of the wire with a layer of solder before you put it thru the hole in the PCB that will give you insurance of a proper electrical contact else you will put a heap of solder on the PCB without a proper contact with the wire itself what is called a dry joint that go for un tinted copper wire only normally all electronic component pins is factory tinted
What is the formula for transient spike computation in an inductive load?
E=I x R. The inductive spike occurs as the circuit is opened. The collapsing magnetic field causes the inductor to become the source of the circuit. For example consider a circuit consisting of a 10 volt battery, a 10 mh inductor, and a 10 ohm resistor all in series. With the switch closed, 1 amp will flow through the circuit (after 5 mS). The 5 mS is the time it takes the current to rise from 0 to 1 amp. This is given by the formual TC=L/R where TC is the time constant in seconds, L is the inductance in henries, and R is the resistance in ohms. It takes 5 time constants for the current to reach the maximum current which is determined by I=E/R (Ohm's Law). The delay is caused by the counter EMF generated in the coil as flux lines cut through adjacent turns of the inductor. After 5 time constants, the current is at 1 amp. When we open the switch, it will take 5 time constants for the current to drop to 0 amps. However, this will not be 5 mS because the resistance is now much larger do to the opening switch contacts. The voltage across the switch contacts will be whatever is necessary to maintain the current flow for the 5 time constants. After one time constant, the current will have dropped to 32% of the maximum current or in this case, 0.32 amps. If the resistance of the switch gap is 1 megohm, the the voltage will be 320,000 volts. More than enough to ionize the air and create a conductive path. If we assume an average resistance of 1 megohm, it will take 50 nS for the current to drop to 0. Of course during this time, the switch contact gets zapped. Placing a diode across the inductor such that the diode is reverse biased with the switch closed will give the current an alternate path as the polarity of the inductor reverses when the magnetic field collapses and the inductor becomes the source. This lowers the voltage from 1,000,000 volts to 0.7 volts. The downside is that the time it takes for the current decrease increases bo the ratio of 1,000,000/0.7. In a relay, this may cause the relay to "chatter" when opening. Adding a zener diode in series anode to anode with the spike suppressing diode will alleivate most chattering problems. A 34.3 volt zener will raise the voltage from 0,7v to 35v and shorten the time by a factor of 50 (35/.0.7).
Purpose of an engineering bench vice?
The purpose of an engineering vise to clamp and hold an object in order to work with it. Most vises are permanently mounted on a work table.
A current of 4.5 A flows in a 3.5 ohms risistor for 5.5 minutes the energy dissipated is?
W=P*t=(U*I)*t=(R*I)*I*t=R*I^2*t
=> here with I=4.5 A, R=3.5 Ohms, t=5.5 mins * 60 s/min = 330s
W= (3.5 * 4.5 * 4.5 * 330) J = 23388.75 J
