AC2 Fundamentals Unit 1 – RLC Circuits
Exercise 1 – Series RLC Circuits
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to analyze series RLC circuits by using
calculations and measurements. You will verify your results with an oscilloscope.
DISCUSSION
- In a series RLC circuit, the total impedance is the combination of the oppositions contributed
by each component. Total impedance (Z) consists of a resistive and reactance component. - Net reactance is the difference between the two reactances.
- The equivalent circuit behaves as a series RL or RC circuit, depending on which reactive
component is larger. - Once total impedance is known, Ohm’s law can be used to determine circuit current.
- Voltage across each component is found using Ohm’s law and series circuit basics.
- In a series RLC circuit, total voltage is found with this equation:
VGEN = sqrt [V^2 R + (VC − VL)^2 ] - The impedance phase angle is found using one these equations:
Zθ = arctan (XNET/R)
θ = arctan (VNET/VR)
where XNET is the total reactance
VNET is the total reactive component voltage - Since the amount of reactance is frequency dependent, circuit values will vary with changes
in the frequency of the applied voltage.