# Oscilloscope waves explanation help!

#### BioStudent

Hi there!
For an intro to physics lab class we did an experiment using oscilloscopes. As we increased the voltage the amplitude of the sine wave decreased. Why is that? I feel really stupid asking because I should know, but I'm confused.
Thank you for any and all help!

#### studiot

Depends what you mean by "increase the voltage" ?

If you mean that you increased the voltage per division setting on the scope then the same signal would look smaller.

Scope settings are shown in volts per division, (usually cm).

This means that 1 volt signal will appear 1cm high on a setting of 1V/cm
Change that to 10V/cm
and the same signal will only appear 0.1cm or 10mm high.
Change the setting to 0.1 volts/cm or 100milliV/cm
and the signal will appear 10cm high.

Does this help or did you mean something entirely different?

#### BioStudent

Depends what you mean by "increase the voltage" ?

If you mean that you increased the voltage per division setting on the scope then the same signal would look smaller.

Scope settings are shown in volts per division, (usually cm).

This means that 1 volt signal will appear 1cm high on a setting of 1V/cm
Change that to 10V/cm
and the same signal will only appear 0.1cm or 10mm high.
Change the setting to 0.1 volts/cm or 100milliV/cm
and the signal will appear 10cm high.

Does this help or did you mean something entirely different?
Thank you so much for your reply! I'm not sure what settings were used for the scope. We had a generator connected to the scope using a BNC cable and bananas plugs (I think). As we increased the voltage on the generator the amplitude of the sine waves on the oscilloscope decreased. We started off using 2mV, then went to 5, 10, and 20 mV.

#### studiot

So what else was connected.

Can you draw a block diagram showing everything?

#### BioStudent

So what else was connected.

Can you draw a block diagram showing everything?
I'm pretty sure we just used a BNC to banana plug connector to connect the banana plug from the signal generator to the oscilloscope. Its not letting me upload a block diagram, its saying its too large. I'm really sorry if I am leaving out pertinent information, this is just what I understand of it. Thank you so so much for all of your help!!

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