5/5/15 - Oscilloscopes

Today we start with a small demonstration of a device called an oscilloscope. A stream of electrons hits a chemical screen to produce a colour, but since we can create electric fields, we can therefore move a particle with charge's trajectory.

The oscilloscope shoots a stream of electrons at the screen while plates with potential differences change the trajectory.

An older oscilloscope which we will use for our lab experiments.

Here the demo oscilloscope is projecting a dot on the screen, the dot is centered with the current configuration.

The potential on the plates is changed and the dot moved since the field is different.

Here we have the same result on the oscilloscope, but an interval circuit is moving the for us at a constant interval.

When we reduce the interval enough, the dot becomes a line due to the electrons leaving a mark on the chemical screening.

Here we explain what happened when a light bulb filament is ignited and illuminating the surroundings.

Here we try to explain the voltage as a function of time on the plates moving the stream back and forth on the screen. We find that to produce the effect we saw on the screen, the voltage had to be a linear rise and it would have to repeat. Since it's not possible for a dis-continuity to exist, we add the dotted lines to represent a very rapid change.

Here we apply the DC signal to the oscilloscope and see the line move upward due to the potential difference.

Here we simply explain what happened to the line as we applied the current signal.

Here we derive the distance traveled by the electron in terms of symbols, and we found that really the only component that can change would be the voltage difference, therefore causing the change in heights.

We hook up the oscilloscope and a function generator, we first try out the function generator with some speakers.We notice that the sinusoidal wave caused a very distinct sound that changed in pitch with the frequency and volume with the voltage.

The oscilloscope with an AC current hooked up, we adjusted the oscilloscope to produce a steady image.

 Here we open an close a DC current switch. We see the line move up and down accordingly to the signal.

We apply a square wave length to the oscilloscope and observe its effect on the screen. As we predicted earlier, the discontinuity cannot be shown as a line so it's omitted.

A positive DC current.

An AC current with a positive DC offset.

The oscilloscope in dual channel with two AC currents, one current's frequency is 3 times the other.

The oscilloscope in dual channel with two AC currents, one current's frequency is the same as the other.

The oscilloscope in dual channel with two AC currents, one current's frequency is 2 times the other.

The oscilloscope in dual channel with two AC currents, one current's frequency is 3 times the other, but the opposite way.

Professor's demonstration of dual channel with the same frequency.

Our setup during the lab to figure out the mystery box.

A table we made that compares each of the connections on the mystery box.

Some final conclusions on the mystery box, we still don't know how it works exactly, but due to the answers from the graph, we attempt to guess what the box does with each signal.