Discharging a capacitor with constant power

capacitor_discharge.py

from pylab import *

C=1200.
V=6.
Q=C*V

P=0.5
R=V**2/P
I=V/R
t=0
dt=10.

vp=[]
tp=[]
rp=[]


while V>2.5:
    V=Q/C
    R=V**2/P
    I=V/R
    Q=Q-I*dt
    vp=vp+[V]
    tp=tp+[t]
    rp=rp+[R]
    t=t+dt
    #print(V)

plot(tp,rp, linewidth=3)
print(t)
print(V)
print(Q)
#plot(tp,rp, linewidth=3)
grid(True)
xlabel('Time [s]')
ylabel('Potential Difference for Capacitor [Volts]')
show()