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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

Can people live in the ocean?

Yes. Bikini Atoll (You may have heard of this famouis atoll) was populated till the US decided they wanted to test Nukes their and kicked the local population off in 1946. Sure, why not? People live on Wake and Midway Islands which are both atolls.

What is the current flowing in a circuit which has two resistors of 4 ohms each connected in parallel to a power source of 24 volts?

Three 214 K Ohm resistors in series is 656 K Ohms. Across 24 volts, that is about 0.03659 milliamperes.

Three 214 K Ohm resistors in parallel is about 71.3 K Ohms. Across 24 volts, that is about 0.3364 milliamperes.

RSeries = SummationI=1toN (RI)

RParallel = 1 / SummationI=1toN (1 / RI)

Current = Voltage / Resistance

Which type of element is used as semiconductors?

Commonly doped silicon is used to make semiconductors, but advancements in organic electronics now mean that semiconductors can be made from molecules made from elements such as carbon, hydrogen, oxygen, sulphur, nitrogen and a few others.

What are the two basic configurations in operational amplifier?

opamp is a device used to amplify ac as well as DC input signals.

It is called as operational amp becoz it is used to perform all mathematical operations. Symbol of opamp indicates the direction of current.

Mathematical formula for converting dc voltage to ac voltage?

I guess Vc=VmSinwt;

Here Vm=Peak Voltage

Vdc=Vm/(2^.5)

Then We Calculate the Impedence of the Circuit.i.e.

Z=(R2+(XL-XC)2).5

Now Idc=Vdc/Z

This is the formula for obtaining Direct Current from Alternating Current.

What are field windings and armature windings in a dc motor and generator?

generators have two types of winding ,

* at armature also called armature winding( winding around shaft , we can say), which is the moving part. note that armature also consists of magnets along with windings. hence produces field arount it.

* and at stator also called field winding, because when armature rotates its flux(field) is cutted by the stator windings and produces mutually induced e.m.f in it( in stator windings off course) causing current to flow.

this current also produces some electric field around it which is in return cutted by the armature windings hince a little amount of e.m.f ( also called back e.m.f) produced in armature due to stator winding current.

know this current in armature (due to back e.m.f produced by stator winding) produces additional field , hence causing more current in stator winding. this is the reason that why stator windings are called field winding( as they cause electric field of armature stronger and cause more current in output).

note that out put is taken from the stator windings in generators.

Use of transistor 7812?

7812 is not a transistor. It is a three lead voltage regulator integrated circuit. Its maximum input voltage should be near 35 volts. The minimum input voltage should be near 14 volts. The output will be 12 volts.

What is the difference between a diode and scr?

A diode mainly consists of only 2 terminals(anode,cathode).A SCR mainly contains one more terminal called GATE.The main purpose of the gate in an SCR is just to provide pulses.The main draw back of SCR is it is not fully controllable device.

Why sudden switching produces spikes in voltage?

This occurs due to a sudden "cut-off" or suspension, or release of voltage. Sometimes this can even cause a breaker to trip, or a GFI unit to trip, due to the sudden spike.

A2.) As a magnetic field collapses it induces currents in conductors nearby.

The faster the field collapses the higher the voltage.

This applies to inductive circuits. Although an inductor (coil) may not be physically present in any particular circuit, there is always inductance present, by the very wires themselves.

All electrical circuits have reactive components - parts of the circuit that hold charge, such as inductors and capacitors. When switching these elements out, the charge they are holding cannot instantly go to zero; it's released in the form of a spike. When switching these elements into a circuit, a sag can result due to these elements attempting to absorb power. Switching in can also result in spikes due to the capacitive and reactive elements creating a "tank" circuit (the voltage will sag slightly, then spike). At their resonant frequency, the reactive and capacitive elements will cause voltages to spike signficantly (for more information, look up LC tank circuits). Similarly, switching out can result in the trapped energy between capacitive and reactive elements to pass back and forth at a resonant frequency, spiking the voltage.

What are static capacitors?

These are capacitors that are connected in a circuit in parallel with the load. A circuit with low, lagging (inductive) power factor (pf) can be improved by those static capacitors by decreasing the circuit's inductive reactive power (wasted power consumed for magnetic induction of motors) reducing it's pf to almost unity (1).

A circuit with low power factor means it consumes more power which is actually not being used or wasted. Putting a static capacitor for pf correction improves the circuit.

Comment

Power-factor improvement doesn't 'improve the circuit', and it has no effect on the power of a load, it merely reduces its load current.

What is the total resistance of three resistors in parallel?

1/Rtotal = 1/R1 + 1/R2 + 1/R3 1/Rtotal = 1/0.2 + 1/0.4 + 1/0.5 1/Rtotal = 10/2 + 10/4 + 10/5 1/Rtotal = 100/20 + 50/20 + 40/20 1/Rtotal = (100 + 50 + 40) / 20 1/Rtotal = 190 / 20 Rtotal = 20 / 190 = 0.11 ohms Note that in any circuit where a number of resistors is connected in parallel, the total resistance will always be smaller than the smallest resistor of the bunch. That's a quick way to check and see if your work is anywhere in the ball park.

What is power dissipation in resistance?

The power P dissipated by a resistor will leave the resistor in the form of thermal energy (heat). It will get hot due to the fact that the material it is made of opposes current flow, and when current is forced through it by a voltage source, it gets hot in response. Resistance R could be thought of as "electrical friction" in many cases. Resistance is measured in ohms, voltage V in volts and current I in amperes (amps). The power in watts dissipated by a resistor with the value R will be the square of the current through it times its resistance. P=I2R The power in watts dissipated by a resistor with the value R will be the square of the voltage drop across it divided by its resistance. P=V2/R Because E means energy we take V for voltage. The power in watts dissipated by a resistor with the value R will be the voltage drop across it times the current flow through it. P=IV All three statements are true, and they all say the same thing. The mathematician might say that the variable P is being expressed in terms of the variables I, V and R. As all the statements are true, it can be said that P=I2R=V2/R=IV.

What voltage is led?

A: The voltage for LEDS varies from 1.8v to even 5 volts. These voltages also varies from color to color. A 5 volt LED usually has a tiny resistor in series so the led can be tied across a 5v buss as a unit. Some manufactures actually has two LEDS in series to provide more brightness

What are the disadvantages of asynchronous counter?

Counter circuits made from cascaded J-K flip-flops where each clock input receives its pulses from the output of the previous flip-flop invariably exhibit a ripple effect, where false output counts are generated between some steps of the count sequence. These types of counter circuits are called asynchronous counters, or ripple counters.

Where can one buy a cheap pair of flip flops?

A cheap pair of flip flops can be found at any local dollar store during the spring and summer seasons. Some stores will have them on sale for as low as seventy five cents.

What are the types of technology?

žAlternative technology žAppropriate technology žDisruptive technologyžDomestic technology žHigh technologyžIndustrial technology žBiotechnologyžMicro technology

What is the importance of chemistry in electrical engineering?

There are several reasons why chemistry has such a high importance in electrical engineering. It is important because chemistry helps you to know more about the materials you are using and working with. Knowledge of how materials and products work together is needed in the engineering field.

Name the three basic methods that are used to vary the speed of a DC motor?

speed of a dc motor can be varied by mainly two methods:-

1)field control method

2)armature control method

further ,

field control method can be divided in 3 parts:-

1)field rhestat control method---speed variation is acomplished by means of a variable resistance inserted in series with shunt field

2)reluctance control method---by changing the reluctance of magnetic circuit by choosing right material..

3) field voltage control method-requires variable field voltage supply.

and armature control method can be divided in 3 parts :-

1)armature resistance control---variable resisitance connected in series with armature

2)shunted armature control.

3)armature voltage control.

------------mrityunjay pandey

(kiit university ,btech 2nd year)

Can you use a 25 microfarad 370 volts capacitor in place of a 30 microfarad 370 volt capacitor?

Not a good idea, without knowing more about the circuit in which it's installed.

Presumably, the 440v capacitor was selected because its max voltage rating (440v) is

higher than the instantaneous voltage to be expected at that point in the circuit. By that

criterion, the voltage at that point in the circuit may exceed 370 volts, and your proposed

replacement component won't hold it.

How many milliamps in 48.8 watts?

Milli amps is a measure of current whilst watt is a measure of power.

The missing element is voltage as the formula is:-

Power = Voltage * Amps

ie power in Watts is the product of Volts (in Volts) times Amps (in Amps)