|
The resonance frequency of this RLC circuit is 88.9 Hz. The resistor value associated to critically damped oscillations is 17.9 Ohm. Just for convenience, the resistor at the bottom (probe) makes it up to 100 Ohm with the resistor of the parallel RLC. The Q factor is 0.5 (probe resistor not included). The amplitude of the input is 10 Volt oscillating at 88.9 Hz.
When the circuit is driven at the resonance frequency, the impedance of the parallel RLC is equal to R. If the switch in series with R is open, then the RLC impedance is infinite.
The effect of infinite impedance can be observed by looking at the voltage drop across the probe resistor, which becomes zero after a short transient period.
For an infinite R, the parallel RLC circuit is "totally opaque" (a "tank") to the signal oscillating at the resonant frequency.
### BONUS ###
At resonance, the current's magnitude through either L or C (50 mA) is Q times the magnitude of the input current (100 mA).
To observe "current magnification", close all switches and wait for the transients to extinguish.
To observe critically damped oscillations, disconnect the parallel RLC from the input and close the switch in series with the resistor.
### WHAT TO REMEMBER ###
"Only the AC component of the input signal oscillating at the resonant frequency of the parallel RLC is not allowed to go through the branch containing the parallel RLC itself"
To see this effect, change the frequency of the input signal and observe the magnitude of the voltage drop across the probe resistor, which will always be larger with respect to the resonance case.
|
