Hello, My data gravely perplexes me. I've set up a simple series RC circuit with an AC emf of 14V @ 20Hz. Resistor and capacitor values are 3.9E4 ohms and 4.7E-5 farads respectively. Ideally, the voltage across the resistor should be a simple sine curve, since this is basically an RLC series circuit with L=0. However, what I'm getting off of a digital voltmeter (outputting data to the computer) is a strange but pretty series of superimposed sinusoidal curves. A general pattern can be discerned over a period of seconds, which is what confuses me. I'm thinking the large pattern is caused by premature discharging of the capacitor midway through an emf cycle, thereby causing perturbations in the resistor voltage. The time constant may also be slyly manifesting itself, although i've recieved considerable opposition to this idea. Please try to destroy the interpretations put forth here. I can't seem to upload my graph bcoz it exceeds the upload size limit.