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RC Filter

RC calculation

T=RC, so:


          Time

  Resistance   Capacitance

or


      mS	  

  Kohms   uF

or


    Seconds

  ohms      F

The result gives you 1T. This is 1 time period. So for 1000uF and a 1K resistor T = 1000mS

For charging and discharging a capacitor:

1T 63%
2T 86.5%
3T 95% (this tends to be the default usage with 95% considered basically there)
4T 98% (this tends to be considered as 100% charged / discharged)
(in theory 100% is infinite)

Voltage is irrelevant to this. If a 12V supply was connected via 1K to a 1000uF cap it would take 1000mS to reach 7.56V, 3000mS to reach 11.4V. Its exactly the same for discharging a capacitor.

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