dc and ac circuits

Therefore the non-resistive of a coil to a.c. due to the varying magnetic field is called capacitive reactance Xc. Unit of Xc is also Ohm The current leads the EMF by 90 o and the phasor diagram is: For DC, Xc becomes infinite and hence, capacitance block DC flowing th..

AC Circuit Containing Resistance only - Let an AC source of EMF E be connected to a pure resistance R. The instantaneous EMF from the source is given by E = E o sin w t From Ohm's law I = E/R = E o /R . sin w t I = I o sin w t The variation of E and I shows that both r..

Let an AC source be connected across pure inductive elemen..

AC Circuit Containing Resistance, Inductance and Capacitance Circuit (LCR in series) - When an AC source is connected in a circuit with a resistance and a reactance together, the current varies initially in a complex way. After sufficient time, a si..

Let an AC source be connected across a pure inductive element. If the alternating current I = I o sin w t flows through it. Then According to Kirchhoff's Law E = E o cos w t or..

When an AC source is connected in a circuit with a resistance and a reactance together, the current varies initially in a complex way. After sufficient time, a sinusoidally varying current persists in the circuit. This steady state current has a frequency equal t..

>As the armature rotates about an axis perpendicular to the magnetic field, it keeps on changing its relative orientation with respect to the field Thus the flux keeps on changing continuously with time This change in magnetic flux induces an emf If the outer terminals of the armature are connected..

The impedance of LCR is In expression (1), I o has different values for different frequencies. But I o has a maximum value when Z is minimum. i.e., when X L = X L c or Z = R since w = 2 p f This frequency for which the current in AC circuit reaches a peak value and the A.Ch..

Electric Generator (AC) - The electric generator converts mechanical energy into electrical energy. The two types of generators are DC and AC generators: DC Generators - A cycle dynamo and a car dynamo are examples of DC generators. They produce ..

>Total work done or energy spent in maintaining current over one full cycle. The second term is zero over complete cycle i.e., Therefore, The quantity cos q is called the power factor of the AC circuit and we kn..