Electronics Engineering

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

A quadrillion and one.

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I read that it can go up to 80 Volts, any more and it becomes a shock hazard to the operator.

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.

Before Christ

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)

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.

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)

Put simply, no, but devices that do that are built with transistors and other components. All transistors do is convert voltage to current, with various complications.

To convert DC to AC you use an inverter - which isn't a helpful name because there is another electrical system called an inverter that simply inverts the waveform. They're pretty well covered on wikipedia, but a simple description would be they involve using transistors to quickly switch on and off a DC supply to approximate the AC supply.

Because the series resonant circuit has the lowest possible impedance at resonance frequency, thus allowing the AC current to circulate through it. At resonance frequency, XC=XL and XL-XC = 0. Therefore, the only electrical characteristic left in the circuit to oppose current is the internal resistance of the two components. Hence, at resonance frequency, Z = R. Note: This effect is probably better seen with vectors. Clarification: Resonant circuits come in two flavors, series and parallel. Series resonant circuits do have an impedance equal to zero at the resonant frequency. This characteristic makes series resonant circuits especially well suited to be used as basic pass-band filters (acceptors). However, parallel circuits present their maximum impedance at the resonant frequency, which makes them ideal for tuning purposes.

OK, well Earth Loop Tester have a permanent magnet in it. When we rotate it, the flux cut the the conductor and consequently an emf is produced. As we connect the two point of the tester to the earth it complete the circuit and current start flowing through it.

The ratio of voltage and current give us the Impedance of Earth.

Because Voltmeter measures potential difference BETWEEN two points so it should be connected to these two points and the only way for circuit and voltmeter to be both connected to the same 2 points is in parallel. Ampermeters measure the current THROUGH some circuit so the same current that is flowing through this circuit should flow through the ampermeter too. The only way is to let the current going through the circuit to go through the ampermeter later or before, so you have to connect ampermeter in series with your circuit. The fact that voltmeters have high resistance while ampermeters have low resistance is the side effect of the way how they are connected to reduce the error introduced by devices into measured value.

advantages are being able to communicate, and transmit information over long distances. unfortunately though they cannot transmit into space on there own, and can break - being made out of fine glass and plastic that they are!
disadvantages is that you get splinters from the fibres and the really hurt trust me ive had a few of those little suckers ha de ha