RLC Series Circuit

Electricity and Magnetism > AC Circuits

DCS# 5L20.20 v.2

RLC SERIES CIRCUIT WITH 4-CHANNEL SCOPE

APPARATUS

function generator	107-01-A
500 - 6-8 ohm audio transformer	214-01-D
60 mH inductor	214-01-D
1 uF capacitor	101-09-G4
decade resistor	214-01-A
1:1 isolation transformer	202-08-B2
4-channel oscilloscope with camera	202-08-B-5

DESCRIPTION

All four signals - V_in, V_R, V_L and V_C - can be displayed simultaneously.

This setup can be used to show:
    resonance in a series RLC circuit.
    the broadening of the resonance peak with increasing R.
    phase relations in an RLC circuit.
    the relative sizes of X_C and X_L at frequencies above and below resonance.
    phase relations in RC and RL circuits: short the inductor or capacitor with a wire.
    transient oscillations in an RLC circuit: use the Pasco function generator/amplifier square wave output.
RC and RL time constants: short inductor or capacitor and use square wave mode of function generator.

NOTES: f = [2π√(LC)]^-1 = 650 Hz; Start with R = 100 ohms.

Note that V_R does not have the same amplitude as V_in at resonance because of the resistance (6 ohms) of the inductor.

Adjust the camera aperture so that the colors of the traces are apparent in the projected image.

Color code:
    V_in (Ch1) is yellow,
    V_R (Ch1-Ch2) is red,
    V_L (Ch3) is purple,
    V_C (Ch4) is green.