[Prev][Next][Index][Thread]
Current distribution in resonators
Hi All,
In the photos referenced below I am showing the results of experiments I
have performed to show the average current in different parts of the
resonator. These experiments are very simple and give a good visual affect
of what the standing wave looks like. I think Terry has been doing some
very nice work with optically coupled current sensors (correct me if I'm
wrong Terry), which may give better information than judging the brightness
of a lamp. The lamp experiment gives a very good feel as to what is going
on though, especially if they are viewed real time while the frequency is
changed a bit.
The first photo shows 11 incandescent lamps placed along the resonator to
show the average current at that particular spot.
http://www.aros-dot-net/~gbyrd/tesla/lamps.jpg
For some funny reason the lamp at the bottom of the resonator does not look
as bright as the lamps just above it? The lamps are a type 7387, 28 volts -at-
40 ma. A lamp is non-linear, so current value is hard to judge just by
looking at brightness. Even with the lamp experiment, I can't help thinking
it resonates exactly as a lumped circuit. The TOTAL energy is continually
changing from capacitive energy into inductive energy, and vice verse,
every 1/4 cycle. The LED experimant can be seen here:
http://www.aros-dot-net/~gbyrd/tesla/leds.jpg
The LED experiment is quite interesting. Even with no top load, except a
small screw, the LED at the very top of the coil is glowing some! The LED's
indicate the current (standing wave) is alsmost linear. Lumped circuit? For
all practical purposes, YES! A lumped component like a capacitor, when
combined with an inductor, can cause a reflection property similar to a
reflection from an open circuit in a transmission line.
The ratio of length to diameter in this coil is close to 1:1. I think if
the highth is much greater than the diameter, the theoretical 1/4 sine wave
shape suggested by transmission line theory may start to show.
Have fun, Duane