124-06 AC Ciutcuits - _AC Circuits PHYSICS 124 EXPERIMENT...

_____AC Circuits
PHYSICS 124 EXPERIMENT NO. 6
AC CIRCUITS
The Oscilloscope
The oscilloscope is an instrument which measures voltage as a function of time.
While a few oscilloscopes now use liquid crystal displays (LCD), most
oscilloscopes (including the ones you will use) accomplish this by using a cathode
ray tube (CRT). Cathode ray tubes have been around for more than a century, yet
they still are basic components used in television sets and computer displays.
The oscilloscope drives the electron beam around by changing the electric field
between two conducting plates and thus provides an electrostatic force = q
to a charge q . Two sets of plates are used; one set drives the electron beam up and
down depending on the value of an input voltage, and other set drives the electron
beam from left to right with time. This measurement is usually repeated many,
many times a second, so that to the eye it appears as if a constant pattern were
being traced on the oscilloscope just like the eye perceives a rapid sequence of still
pictures as a “motion picture” or movie.
RC Circuits
You will now use the oscilloscope to study some properties of alternating current
(AC) circuits using capacitors and/or inductors. Unlike simple, direct current (DC)
components like resistors, the behaviors of these circuit components depend on the
rate of change of the input voltage/current (i.e., the frequency of the driving