Connecting passive low pass filters in series, reduces the dc voltage.
Maybe it is very simple but would you explain a little bit to me about the low pass filters effects on dc.
Filters don't reduce dc without a load by the way.

Source 12VDC(with little ripple)
Load 20 Ohm.

Filter section(RC lowpass passive)

If i take the output of the first filter,
500 Ohm 1mF (cutoff around 0.3Hz)---Out ~7VDC---

If i take the output of the second filter also current draw reduces a lot.
500 Ohm 1mF ---Out ~0.20VDC--- etc.

Thank you.

 

The 'R' in RC is a series resistor. Any current flow through such a filter will cause a voltage drop.

 

Understood now.
So the cap is behaving like an open circuit (because capacitors block dc), and the series resistors then are acting like a voltage divider. I think i kind of got it.
That explains why i get reduced voltage between two filters.

 

By the way, some person also answered me in stack exchange, it came pretty clear just to share,

" The load voltage will drop by the output_current x filter_resistor. Its just ohms law.

So in your case, when using one filter stage, it will drop by 500mV for every 1mA of load current.

So in your case, when using two filter stages, it will drop by 1V for every 1mA of load current. "