  We present a CCD photometric survey for the search of variable stars in four
open clusters namely Berkeley 69, King 5, King 7, and Berkeley 20. The time
series observations were carried out for 1 and/or 2 nights for each of the
clusters in the year 1998, which have led to identify nineteen variable stars
in these clusters. Out of these 19 variable stars, five stars show delta Scuti
like variability and two stars show W UMa type variability. In other stars, we
could not find the periods and hence the type of variability due to the lack of
sufficient data. The periods of delta Scuti type stars are found to be in the
range of 0.13 to 0.21 days, whereas the two stars in the cluster Berkeley 20,
which showed W UMa type variability have orbital periods of 0.396 and 0.418
days, respectively. Using the Gaia data, the basic parameters of the clusters
Berkeley 69, King 7 and King 5 are also revised. The age and reddening are
estimated to be 0.79 \pm 0.09 Gyr and 0.68 \pm 0.03 mag for Berkeley 69, 0.79
\pm 0.09 Gyr and 1.22 \pm 0.03mag for the cluster King 7 and 1.59 \pm 0.19 Gyr
and 0.63 \pm 0.02 mag for the cluster King 5, respectively. Signature of mass
segregation is found in the clusters King 7 and King 5.
