First multicolour photoelectric light curves of the southern early-
type eclipsing binaries GW Car, V685 Cen, V742 Cen and V764 Sco were
obtained in the years 1969, 1974, 1977-8 at the Leiden Southern Station using
Walraven V BLU W filters. New orbital periods 0.86446 days and 1.54263 days
were found for V742 Cen and V764 Sco, respectively. The long-term orbital
period decrease was detected in GW Car. Our light-curve analysis accomplished
by Wilson-Devinney’s code found an almost semi-detached configuration for
GW Car and revealed that V685 Cen, V742 Cen and V764 Sco are detached
systems.