If the unwanted offset occurs only at higher frequencies and not at the
lower frequencies then there may be an unwanted capacitive influence on the
measurement that appears at the higher frequencies.
Is your scope probe in AC mode?
If so, then try switching it to DC mode and see if that works.
You Said:
I’m doing an RLC lab tomorrow. I’m using a coil with an inductance of about
0.9 H and a resistance of about 60 ohms (both measured using a handheld
meter). I connect it in series to a capacitor of 1 microfarad and an
additional resistor of 100 ohms. So resonance is around 180 Hz. I use a
Pasco function generator with an amplitude of about 5 V.
Measuring the voltage across the coil does give a peak around there. At low
frequencies, the voltage goes to zero, but on the high-frequency end the
voltage does not go to zero but instead levels off at quite a high value
(maybe 1 V or more).
What’s the primary reason the voltage stays so high across the coil at high
frequencies? (And when I say high, I mean above a few hundred hertz, not
super high.)
- JZ
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Gerald Zani
Senior Engineering Technician
Brown University School of Engineering
(401) 863-9571