  Ground-based long-term optic variability of AM Her, covering the period
between 2003-2008, has been conducted to study the features seen in both low
and high states of the system. Low-state analysis shows the presence of
short-term, low-amplitude light variations of about 0.02-0.03 mag with a mean
power time between 16 s and 226 s. Brightness variations on the order of 0.7--2
mag, which could be due to the stellar activity of the component in the system,
are also detected. A total of 30 years times of minimum light given in the
literature are combined with nine times of minima obtained in this study. We
represented the (observed--calculated) diagram by a parabolic curve and also by
two broken lines. Under the assumption of a parabolic variation, we estimate an
increase in period, dP/dt=7.5(1.2)x10^{-9} days yr^{-1}, with a mass transfer
rate of dM/dt = 8(2)x10^{-9} M_{\odot} yr^{-1}, in agreement with the previous
findings by a different method.
