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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
A redox mediator is a hyperbranched polymer having redox moieties (e.g. ferrocene) incorporated into its structure and/or chemically bonded to its periphery. It is attached to an electrode and assists in transferring electrons between the electrode and a redox enzyme.
What type of motor is used in dam gates?
Generally for big and major dams,motors are alone not used,all this type dam gates will be controlled manually.Because it is not easy to conrol the large dam gates by motors.
But for the dams with single gates,used for irrigation purpose,in canals,we can use the synchronous reversible motors to control such type of dams.
black black brown black is just some fool's uneducated guess.
The correct answer is:
Brown, black, gold which translates to 1,0 x point 1
or 10/1 = 1ohm
Look at http://www.hobby-hour.com/electronics/1ohm-8ohm2-resistors.php for more.
A: Signal travel in a line of sight on mountains there are repeater to by pass the mountain to the next town, A regenerative repeaters will restore this signal before it send it out again
What advantage do regenerative repeaters have when used for digital communication?
When any digital signal is transmitted over a pair of wires, it degrades in amplitude. Regenerative repeaters receives the incoming signal, extracts the clock, then regenerates the original signal as a clean digital square wave as if it was the original signal transmitted from the source. Thus the name repeater.
Dear All PGDC asspirants
NPTI Nangal & Nayvelly are new institutes among all, but a decreasing priority order may look like as.......
1. NPTI BADARPUR
2.NPTI DURGAPUR
3.NPTI NAGPUR
4.NPTI GUWAHATI.
5. NPTI NANGAL
6. NPTI NAYVELLY.........
BUT last year guwahati has 100% placement meanwhile others have more or less same but satisfactory.
Placement is a game of time and fortune so dont bother about that.
Good luck
What happens to the clipping level when you freeze a diode?
Clipping level increases.
For example, if the clipping level was 2V before freezing, it will clip at a voltage greater than 2V when frozen.
Gold is diffused into silicon pn junction diode why?
In order to shorten the switching time, diodes sometimes are doped with gold or other deep-level impu-
rities to create more generation centers and to increase the carrier recombination rate.
What is the rms current for an 8.0 µF capacitor attached to a 120 V rms 60 Hz source?
The RMS current for an 8.0 µF capacitor attached to a 120 V rms 60 Hz source is 39,798 amperes.
Is it safe to connect a 300W amplifier to a 60W speaker?
Safe, as in you're not going to electrocute yourself, yes.<br />
But, the amp will be able to put out more power than the speakers can handle, so don't turn the volume up all the way or you will fry the speakers.
What is the purpose of a resistor in a regulated power supply?
Need more information - a typical regulated power supply would include dozens of resistors, each for one of several different reasons. Which resistor are you asking about?
In its simplest use a resistor in a circuit is used to limit the amount of current flow, or to decrease the amount of voltage applied to a device. One example is you had a 12 volt battery and you need/ wanted to connect it to a device that ran on 9 volts then a resistor can be chosen to reduce the 12 volts to the 9 volts required.
Is it safe to charge a battery while in use?
This depends on the type of battery. Car batteries are always charged while in use. With other types of batteries, this is not recommended and may result in a battery explosion or damage to the device the battery is powering.
Will changing the battery from 6v to 12 v affect gas gauge reading?
If it is in your car then no, why do you have a 6v battery in your car in the first place it should be a 12v.
I think this question was answered at Instructables.com.
The permanent magnet moving coil instrument is the most accurate type for D.C. Measurements. The working principle of these instruments is the same as that of the d'Arsonval type of galvanometers, the difference being that a direct reading instrument is provided with a pointer and a scale
(Fig) Permanent magnet moving coil instrument
Construction of PMMC Instruments
- The constructional features of this instrument are shown in Fig.
- The moving coil is wound with many turns of enameled or silk covered copper wire.
- The coil is mounted on rectangular aluminum former, which is pivoted on jeweled bearings.
- The coils move freely in the field of a permanent magnet.
- Most voltmeter coils are wound on metal frames to provide the required electro-magnetic damping.
- Most ammeter coils, however, are wound on non-magnetic formers, because coil turns are effectively shorted by the ammeter shunt.
- The coil itself, therefore, provides electro magnetic damping.
Magnet Systems
- Old style magnet system consisted of relatively long U shaped permanent magnets having soft iron pole pieces.
- Owing to development of materials like Alcomax and Alnico, which have a high co-ercive force, it is possible to use smaller magnet lengths and high field intensities.
- The flux densities used in PMIMC instruments vary from 0.1 Wb/m to 1 Wb/m.
Control
- When the coil is supported between two jewel bearings two phosphor bronze hairsprings provide the control torque.
- These springs also serve to lead current in and out of the coil. The control torque is provided by the ribbon suspension as shown.
- This method is comparatively new and is claimed to be advantageous as it eliminates bearing friction.
Damping
- Damping torque is produced by movement of the aluminium former moving in the magnetic field of the permanent magnet.
Pointer and Scale
- The pointer is carried by the spindle and moves over a graduated scale.
- The pointer is of lightweight construction and, apart from those used in some inexpensive instruments has the section over the scale twisted to form a fine blade.
- This helps to reduce parallax errors in the reading of the scale. When the coil is supported between two jewel bearings two phosphor bronze hairsprings provide the control torque.
- These springs also serve to lead current in and out of the coil.
Torque Equation.
The torque equation of a moving coil instrument is given by
As the deflection is directly proportional to the current passing through the meter (K and G being constants) we get a uniform (linear) scale for the instrument.
Errors in PMMC Instruments
The main sources of errors in moving coil instruments are due to
- Weakening of permanent magnets due to ageing at temperature effects.
- Weakening of springs due to ageing and temperature effects.
- Change of resistance of the moving coil with temperature.
Advantages and Disadvantages of PMMC Instruments
The main advantages of PMMC instruments are
- The scale is uniformly divided.
- The power consumption is very low
- The torque-weight ratio is high which gives a high accuracy. The accuracy is of the order of generally 2 percent of full-scale deflection.
- Using different values for shunts and multipliers may use a single instrument for many different current and voltage ranges.
- Since the operating forces are large on account of large flux densities, which may be as high as 0.5 Wb/m, the errors due to stray magnetic fields are small.
- Self-shielding magnets make the core magnet mechanism particularly useful in aircraft and aerospace applications.
The chief disadvantages are
- These instruments are useful only for D.C. The torque reverses if the current reverses. If the instrument is connected to a.c., the pointer cannot follow the rapid reversals and the deflection corresponds to mean torque, which is zero. Hence these instruments cannot be used for a.c.
- The cost of these instruments is higher than that of moving iron instruments.
What is your observation of resistors in series?
I observe that the total effective resistance of several resistors in series
is the sum of the individual resistance values of the individual resistors.
If you are talking about the primary wires to the transformer then yes they have to be encased in concrete.
Can you give 230V ac directly to bridge rectifier?
Yes, if the diodes that the bridge rectifier are rated for 230V in forward and reverse voltages. Normally you can do a search for the part number on the internet and get specs there.
Multiplexing began in the 1870s. A telegraph operator named Thomas Edison kept falling asleep on the job and invented a machine to record messages incase he fell asleep. Then he decided no reason existed why that machine could not record two or more messages at once. Then he decided that machine could be adapted to be a stock ticker. Then he decided that he could take Mike Farady's extremely expensive light bulb and make it from cheap materials, and he could work at a lot higher voltage so it could run off a generator instead of batteries. And then he decided...
What is the difference between a conductor and an insulator on the basis of conductivity?
it can be easily defined in many ways....
1. conductivity of conductor is higher than insulator....bcoz if we look at periodic table
on left hand side d elements are more likely to loose electrons so dey are conductors.like
hydrogen & lithium is good example bcoz dey have only one electron to loose....
while right side elements are insulators as dey are bounded...and can't easily loose electrons as dey require high energy...helium and all noble gas elements are good example of insulators...
2. temperature coefficient of resistance is positive in conductor so.. on increasing temperature, conductivity will decrease as resistance increases.....and this can not be shown by insulators bcoz dey r tightly bound with each other./
3. in conductor we can increase conductivity by applying d product of mobility and electric field......while in insulators it cannot be done easily.....
What is the dB value for a gain of 10?
10dB It is a logarithmic relationship, so a gain of 20 is 13dB, and a gain of 100 is 20dB
Is Watt Increase in series Connection Off Two Resistor?
No. The power (in watts) would decrease, due to the greater effective resistance.
