I have a capacitor rated 15000 µF, 35V.
So, I charge my capacitor to 15V with no problems using a charging resistor. Now while discharging, I am using thyristor (2N6509G) as my switching device and a coil as my discharge resistor. Coil resistance is about 2 Ω.
Using the discharge equation of capacitor, I calculated the discharge time in this setup, which comes out to be around 81 ms for (assumed) final voltage of 1 V.
In my application, I wish to discharge the capacitor only for 20 ms. But when I do that, the capacitor voltage drops down to 0.9V in just this 20 ms duration instead of the calculated 7.7V (using discharge time calculators online).
If I am not doing anything wrong in the setup, what is it that I am not understanding conceptually? How do I go about discharging capacitors only to some fraction of the stored charge?
Edit: Thank you all for your comments, I am sorry for not being very clear with the details.
So, this is a coil gun model basically. Coil :- Copper magnet wire: AWG 20; no of turns: 650; Coil resistance: 2ohms
I actually used an online calculator for capacitor. Discharge Time Calculator
I used another calculator to get the inductance of this coil which came out to be 8.88mH. Coil Calculator
*Note: This circuit is not my original work.