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I'm attempting to construct the variable phase shift circuit from this video (link takes you to the circuit diagram of it) except that I am using a 1 uF capacitor in place of the .022 uF capacitor. I have been unable to get it to work and I wanted to check if that change was what was causing the issue or if I have made a mistake in my construction of it?

enter image description here

Thank you.

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    \$\begingroup\$ Did you change the value for a reason, or just because that's what you happened to have? Changing a capacitor in a frequency dependent circuit by a factor of 50 is going to get very different results. \$\endgroup\$
    – GodJihyo
    Jan 27, 2022 at 16:04
  • \$\begingroup\$ >unable to get it to work. What did you do? \$\endgroup\$
    – Antonio51
    Jan 27, 2022 at 16:45
  • \$\begingroup\$ @GodJihyo because it was what I had \$\endgroup\$
    – YaGoi Root
    Jan 27, 2022 at 16:58
  • \$\begingroup\$ @Antonio51 I constructed the circuit as described and I get an incredibly small voltage and noisy signal, nothing like the clean phase shift as shown in the video. \$\endgroup\$
    – YaGoi Root
    Jan 27, 2022 at 17:00
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    \$\begingroup\$ @YaGoiRoot I thought as much. Are the rest of the components the same as in the video, or more of 'what you had'? If constructed properly that capacitor being larger wouldn't cause a low, noisy signal, so something else must be going on. We would need to see a schematic at least, and pictures if possible of the circuit you built, also voltage measurements would be helpful. \$\endgroup\$
    – GodJihyo
    Jan 27, 2022 at 17:27

1 Answer 1

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DC quiet point is ok.

For showing the "phased" signal, I used a scope with (x,y) inputs (x=generator, y=output signal) and made what is called a "Lissajous" picture.

Phase can be calculated or measured as usual.

I make a simulation for the original circuit (@1000 Hz, 0 < Rpot < 5k)

enter image description here

Then a simulation @20 Hz with the 1uF capacitor ... variable resistor is now 50k.

enter image description here

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