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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
If I want to be an Electrical Engineer what college do I apply to?
In the US, I would recommend MIT, Carnegie Mellon, California Poly Tech (CalTech), Rochester Institute of Technology, although its ALL WHAT YOU MAKE OF IT, and how much effort you put into your studies. A degree from an accredited State University will give you a lot of Bang for Your Buck.
Ohm's Law states that the current (I) flowing in a circuit is directly proportional to the applied voltage (E) and inversely proportional to the circuit's resistance (R).
I = E/R
Another way of stating Ohm's Law is that the applied voltage (E) is directly proportional to both the current (I) and the resistance (R).
E = IxR.
So, if the voltage (E) is increasing, then either:
- if you know the resistance (R) is staying constant then the current (I) must be increasing - which you would see because you are monitoring it!
or, if the current (which you are monitoring) is actually staying constant, then, for the voltage to be able to increase:
- the circuit's resistance must be increasing
or
- the increasing voltage could be caused by a combination of both increasing current and increasing resistance!
What is PIV value of a half wave rectifier?
A: It realy does not matter half or full wave. the PIV will be 1.41 the RMS input example 100v ac will have a requirement of PIV of 141 volts on the rectifiers.
What are the properties of an op-amp?
Properties of an op-amp are as follows:
1.Very high open loop gain which remains constant over the frequency range in which the device is to be used.
2.Very high input impedance to minimize the current drawn by the circuit with little losses.
3.Very low output impedance
4. They are stable, i.e. not liable to burst into parasitic oscillation.
5. They are free from drift caused by ambient temperature changes.
What is the purpose of a LED in a circuit?
An LED, or light emiting diode, can have many functions. Commonly used as a solid state light emitter, LEDs of nearly any color of light are available, including ultraviolet and infrared.
A less obvious use of a light emitting diode is to detect light. A LED makes a very efficent and narrow band light detector. It will produce electric current in response to light that is about the same wavelength (and therefore color) as when it is used as an emitter.
Another use of an LED is to make a fairly stable voltage reference; A red LED when forward biased will have a steady voltage drop of about 1.8 volts, an orange LED produces a voltage drop of about 2.0 volts, and about 3.5 volts for blue and white emitting LEDs.
LEDs can be used as modulated light emitters to transmit speech, music and digital information. A good example is a television remote control which digitally pulses a infrared LED to change channels, control volume, and so on.
LEDs are used in solid state switches when optically coupled to a photodiode or photo resistor. LED flashlights are very common, and some small light bulb replacements are available, with larger bulb replacements soon to come. Some links are provided below:
Why do you need a parallel circuit to measure voltage?
Voltage is a defined as a difference in potential. So to measure voltage, you need to look at the difference in potential between two different nodes in a circuit. For example, to know the voltage of a capacitor, you are looking at the difference in potential from one terminal of the capacitor to the other. Even if it is installed in a circuit. It is for this reason, that the measurement is across the circuit, or in parallel with it. One common point of confusion in voltage measurement is the way it is presented. Someone will say, that wire is at 5 volts. The "with reference to" part is often left off. We can say this because most circuits have a direct or implied ground, that all other voltages are referenced to. So the correct thing to say would be "that wire is at 5 volts to ground."
How many transistors would you find in a modern laptop?
A laptop today in mid-2015 typically has about 200 billion transistors in it - this includes the TFT LCD screen, CPU, RAM (memory) and many ASIC and controller chips. To put this in perspective, if today's laptop were made with the 1950s ENIAC vacuum tube ('valve') technology, it would require a space of more than 8.8 billion square feet (94,280 feet on a side. That's 17.8 miles on a side - or 28.5 km per side). This could not be done. A 17 x 17 mile square electronic device built using vacuum tube technology would require more electrical power than all the electrical power plants in the United States could produce, to run it.
This estimate is based on the fact that the ENIAC computer had about 18,000 vacuum tubes and required 800 square feet of floor space.
Now one can see why we are truly living in a paradigm shift; why there's now serious talk about transhumanism and enhanced, immortal man-machine hybrid beings.
(The United States is used as an example because that is where the ENIAC computer was designed, built and operated.)
How is the reading on an ammeter be affected when one of the parallel resistors is removed?
decrease to half of its original value
What power inverter do you need for a kettle?
To power a kettle, you typically need a power inverter that can handle at least 1000 watts, as most electric kettles require between 800 to 1500 watts to operate efficiently. It's important to choose a pure sine wave inverter for sensitive electronics and to ensure it has a surge capacity to handle the initial power spike when the kettle is turned on. Always check the kettle's wattage rating before making a final decision on the inverter.
How do you increase the current produced by coils?
to increase the turn of the coil
ANSWER: Nobody can increase the current of a coil it actually losses power because of IR drop. from the source to the final output will always be less unless the current is amplified by an active device like a current amplifier where the power is from another source.
Do you see a light when the LED diode in the reverse bias?
Not usually, unless you mean a LED. It depends of the kind of diodes. LEDs will emit light but not most regular diodes, though some may produce infrared light.
In the case of LEDs, the answer is yes. When an electron crosses the PN junction and falls into a hole, it emits a photon. The frequency depends on the energy, which is determined by the forward bias voltage. That is why a red LED requires more voltage than an IR LED, and less than a green LED.
So a regular diode with a forward drop of about 0.7V is emitting infrared (IR) light. However, most of the photons are reabsorbed in the semiconductor body or stopped by an opaque case. An LED is a special diode doped for a higher voltage and constructed to let as many of the photons out as possible, set in a reflector and usually with a lens cast into the plastic case.
There are a few glass-cased diodes which emit a deep red light, that I observed in a few audio amps. They drop more than the typical silicon diode's 0.7V. But overall, you typically cannot see the light emitted in a rectifier diode due to the absorption of the case and the semiconductor itself, and the fact that it is usually infrared.
You might try some experiments yourself by removing the IR blocking filter that is normally installed in webcams, or find an IR sensitive security camera. All CCDs (the light sensing element in a video camera, digital camera, or webcam) are sensitive to infrared, but most have had a filter added to block IR so as not to spoil your photos. Then get some glass cased silicon diodes, point contact will have more viewing space, and a 9V battery and a 220 ohm resistor to put in series to limit the current. This will give you about 36mA through the diode.
Then point the camera at it and turn out the lights or put it in a light-tight box and look for a glow from the diode.
FM signals can be detected using a frequency discriminator or a phase-locked loop (PLL) demodulator. The frequency discriminator converts the frequency variations of the FM signal into amplitude variations, which can then be amplified and filtered to recover the original audio signal. In a PLL, the incoming FM signal is compared to a locally generated signal, allowing for the extraction of the original information by tracking the phase differences. Both methods enable effective retrieval of the modulating audio or data signal from the FM carrier.
Where does the name boolean come from?
The term "Boolean" is derived from George Boole. en.wikipedia.org/wiki/George_Boole
What are uses of series and parallel capacitor combination?
Capacitors may be connected in series to provide a capacitance with an effective
working voltage higher than that of any of the individual units, (but the effective
capacitance is less than that of any individual.)
Capacitors may be connected in parallel to provide an effective capacitance value
greater than that of any of the individual units, (but working voltage is equal to
the lowest among the individuals).
A full adder has three inputs - A, B, and CarryIn from the prior stage. It generates a Result and a Carryout with the truth table...
ABC-RC
000-00
001-10
010-10
011-01
100-10
101-01
110-01
111-11
The adder can be a ripple adder, in which the propogation delay depends on the carry "rippling" through the logic, or it can be a look-ahead-carry type, which has constant propagation delay time, at the expense of more logic.
How can amperage in a low voltage circuit be measured?
The question should be, "How should electrical current measured?"
Current is measured in Amperes using an Ammeter placed in series with the conductor of the current. This is impractical, so most ammeters have windings of wire that pick up the field generated around the conductor in question. This winding, or coil, is very carefully sized and the meter very carefully calibrated to yield correct readings of current without a direct connection.
What is a voltage follower Op-amp?
It is an amplifier that has no gain or a gain of one mainly used for isolation .
Capacitance is measured in farads (F), after Michael Faraday. A 1 farad cap is really big; capacitors are usually measured in microfarads (µF), or thousandths of a farad. A power supply in a big power amplifier might have two caps of maybe 12,000 microfarads each
we can't use dc everywhere because dc is hazardous for living beings plus we can't transform mechanical energy into dc power directly.
you can see that we use basically ac appliances at home,also dc but with very low voltages. ac is alternating in nature has zero and negative so if any one get in contact with ac it will result in hazard for the half positive cycle and repelling of body for the negative cycle. but in case of dc, the supply is continuous so it'll hazard the body continuously.
another aspect is generation. as i told earlier that we can't transform mechanical energy into dc power directly means we are generating ac supply in most generating stations where we are dealing with mechanical energy conversion. even dc generator generates ac power but by means of commutation process we convert it into the dc.
so it is not possible to use dc or ac everywhere. we have to deal with the both :)
How do you measure the volt-ampere rating of a transformer?
No need to measure, on the side of every transformer is a nameplate with all the transformer's specifications. Primary and secondary voltages, impedance and winding ratios. Need more info. What are you trying to do? <><><> If it is a small transformer - such as a one that is soldered onto a printed circuit board in a radio or a computer power supply- then it may not have any nameplate. If it is that type of transformer it will have been designed to do its job and you would not need to be able to measure its volt-amp rating. If the transformer is of the larger type that runs on household mains voltage that was mounted separately inside some equipment - such as an old battery charger, television, etc. - then you would have to use some suitable lab test equipment to be able to apply a variable load to its secondary winding (or to the appropriate tap on an auto-transformer) whilst measuring its output voltage and body temperature.
Such tests should never be attempted unless you really know what you are doing and have the right test equipment to be able to do it safely. <><><> As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
What is importance of a polarity test?
HERE'S AN EXAMPLE:
IF THE POLARITY IS BACKWARDS AT A LIGHT FIXTURE THEN THE HOT (120VOLTS) WILL BE THE OUTSIDE OF THE LIGHT BULB SCREW SHELL AND THE MIDDLE PRONG INSIDE THE SOCKET WILL BE THE NEUTRAL -- THEREFORE WHEN YOU CHANGE THE BURNT OUT LIGHT BULB YOU WILL GET SHOCKED BECAUSE THE SCREW SHELL PART IS HOT!! IF WIRED CORRECTLY YOU WILL NOT GET SHOCKED BECAUSE THE HOT (120VOLTS) WILL BE INSIDE THE SCREW SHELL ON THE PRONG AND YOU WON'T BE TOUCHING THAT PART WHEN YOU CHANGE THE LIGHT BULB!!
