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In my setup, a function generator is connected to an amplifier that drives a transducer. The amplifier output is connected to both the transducer and an oscilloscope via a tee connector.

I do not understand why changes in the impedance of my transducer would affect the voltage displayed on the oscilloscope. Changes in the transducer impedance should be downstream of the oscilloscope, right? Please could somebody explain this to me?

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  • \$\begingroup\$ What is the amplifier output impedance vs. frequency? \$\endgroup\$
    – Tim Williams
    Commented Jun 18 at 14:10
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    \$\begingroup\$ Try drawing a schematic that models your setup, it may clear things up. Be sure to include the amplifier output impedance and the transducer input impedance. \$\endgroup\$
    – DavidG25
    Commented Jun 18 at 15:52

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Changes in the transducer impedance should be downstream of the oscilloscope, right?

When it comes to classical circuit analysis we don't consider the term "downstream" because it is meaningless unless "downstream" is via some series resistors or other components,

I do not understand why changes in the impedance of my transducer would affect the voltage displayed on the oscilloscope.

Given what I said above, the oscilloscope input is in parallel with your transducer and, if the amplifier feeding that point has a non-zero output impedance then, changes in the transducer impedance will also affect the oscilloscope reading.

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