K7-26: RLC CIRCUIT - 0.3 HZ RESONANCE

ID Code: K7-26
Purpose: Plot a graph of resonance behavior in a very low frequency resonant circuit.
Description: A series RLC circuit, containing a very large inductor, a 0-50 kilo-ohm resistor, and a 100 microfarad capacitor is driven by a sine-wave oscillator as shown in the circuit above. As the frequency of the oscillator is varied between about 0.1 Hz and 0.5 Hz, the resonance in the system is observed to be about 0.3 Hz. The voltage across the capacitor is shown at various frequencies on an oscilloscope. The scope shows both the signal from the oscillator and the signal across the capacitor.
Availability: Available

The last time we used this apparatus, the resonance seemed to be closer to .5Hz than .3Hz. Is it likely that one of the components is changing with time?