I have a question regarding oscillator outputs and capacitor filters.

I'm trying to build a voltage regulator. I've already calculated and tested the transformer and rectifier, and also the filter part. But when I looked at the output waves from the oscilloscope, the output is straight. Like this:

enter image description here

From the photos I have seen online:

enter image description here

The output waves are very different, is this a normal output from the filter? Take note though that I have a very high value for the farads.

The equation I used to solve this is: C = (Iload / 2) * frequency * Vpp where Iload = 1 A, f = 1Hz, Vpp = 1V

The result is 0.5F or 500000uF.

Is it an acceptable output from the capacitor filter?

Here is my schematic so far:

enter image description here

  • 3
    \$\begingroup\$ Add a 1 amp load to the output. \$\endgroup\$
    – Andy aka
    May 19, 2020 at 13:05
  • \$\begingroup\$ Compute the ripple voltage for that capacitor into the actual load. \$\endgroup\$
    – user16324
    May 19, 2020 at 13:06
  • 2
    \$\begingroup\$ 1Hz is not realistic. AC in most parts of the world is either 50Hz or 60Hz. \$\endgroup\$
    – JRE
    May 19, 2020 at 13:08
  • \$\begingroup\$ Also, I think your formula is off for the capacitor value. Check here and compare to yours. \$\endgroup\$
    – JRE
    May 19, 2020 at 13:10

1 Answer 1


To see the ripple on the output you must add a load in parallel with the capacitor. Add a resistor that will draw about 1A at your desired output voltage.

Also, you must adjust the timescale of your simulation so that you can see the ripples. Have your ac source start at 0.1s and simulate for just one second.


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