Page 169 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

In RLC series circuit,
• Current is same in all three elements
• Voltage across each component depends on their resistance (reactance)
• Total voltage (VS) is the vector sum of individual voltages (i.e. VR, VL, and VC)
• Total opposition to the current flow in the circuit is known as impedance, Z
• The angle between voltage and current is ‘ф’ can be found out from any of the formula.
Frequency response curve

• Resistance is independent of frequency.
• Inductive reactance directly proportional to frequency

• Capacitive reactance inversely proportional to frequency
• At a particular frequency the XL=XC is called resonance frequency
• When a circuit possess inductance and capacitance in such a way that , XL=XC , it is said to be at resonance
• At resonance Z = R
• The frequency at which XL=XC is called resonance frequency fr
1
X X C 2 fL 2 f C
L
2
f 1 1
.2π2
2 4 2 LC
1
f
4 2 LC

1 1
f (HZ)or r (rads)
1
2 LC LC

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CITS : Power - Electrician & Wireman - Lesson 26-29