Hey Guys, I was wondering if anyone could help with this please? You have an RLC circuit, which has R1L and R2C legs in parallel, driven with a variable oscillating voltage. With particular values of R1, R2, L, C it can be shown that the time constant of the R1L and R2C legs are the same. If the 2 legs have the same time constant (and the voltage source is oscillating whatever relevant frequency), what would happen to the circuit?? I'm led to believe there will be some sort of "instability" by the question - will the circuit start resonating perhaps? Many thanks to whoever can give me an answer!!! profqwerty
IIRC, each path will simply attenuate it's tuned frequency, and the attenuation will gradually drop off either side of it.... iirc
Thinking in the frequency domain, the guys above should be right - it's a bandpass filter with a poor quality factor (i.e. wide band). Obviously the ideal LC has a very sharp peak but the resistive losses in this case flatten things out. In the time domain, it's a second order (I think) differential equation which you'd have to pull out using KVL/nodal analysis and the inductor/capacitor equations. The first-order term will give you some idea of the damping, which will in turn tell you whether it resonates or not. Wikipedia has an example of the analysis for a few simpler cases.
