# Capacitor discharging theory vs experiment doesnt match

I am trying to discharge my 1F capacitor over a 47 ohm resistance which i connected in parallel with the capacitor . İ have calculated the time it would take to discharge from 5V to 4V as 10.55 seconds with the following formula : V(t) = V0 * exp(-t/RC). Where V(t) is 4 Volts and V0 is 5 Volts. But whenever i connect the oscilloscope to observe the change in voltage i see this

İt takes exactly 0.2 second from 5v to 4v, any idea that explains why there is a big gap between my anticipated value and the one i measure is appreciated . Have a nice day people :)

• That is a big deviation. From the scope capture it looks like the initial drop is much steeper than it is supposed to be. Could it be that super capacitors are not very "good" capacitors? Their V/I characteristics ony roughly approximate an ideal capacitor? Is the remainder of the curve somewhat as expected? Commented Apr 22, 2016 at 8:15
• What is the Internal ESR of that cap. give the part number/datasheet of the cap. Commented Apr 22, 2016 at 8:20
• Also 0.22 is not exactly 0.2 seconds. And yes I'm being pedantic. Commented Apr 22, 2016 at 8:41
• Brand: KAMCAP Model:5.5V 1F Commented Apr 22, 2016 at 8:45
• Rest of the curve is as it is supposed to be , fully decharged around 5RC seconds. Commented Apr 22, 2016 at 8:46