Capacitor

It will hold the Voltage which was on it when the AC was removed (ignoring subleties like lead and lag and all that fancy stuff wot cats don't undermastand)
Once it is disconnected you can hardly expect it's stored voltage to waggle up and down on it's own can you?
Del

Once it is disconnected you can hardly expect it's stored voltage to waggle up and down on it's own can you?

You will do if you touch it to soon after disconnection.

The discharge current capacitor is of DC (only in one direction) nature but keeps decaying over the time. The rate of decay depends on the load. The equation of the resistance load is

I = (V/R)e^(-t/RC)

V = Capacitor voltage

R = Load Resistance

C = Capacitance

See these links:

http://www.upscale.utoronto.ca/IYearLab/capacitor.pdf (Fig 3)

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capdis.html

- MS