A single diode laser and an electro-optic modulator (EOM)-operated magneto-optical trap (MOT) has been developed for a compact atomic fountain. For generating the required cooling and re-pumping laser beams for the MOT, an EOM operating at 6.58 GHz has been used to modulate the input laser beam. In the trapped cold atom cloud, the population in the two ground hyperfine states ($F = 1$ and $F = 2$) of $^{87}$Rb atom has been varied by changing the power applied to EOM. Using this MOT, the cold atoms have been launched vertically upwards and the launch velocity of atoms has been measured. Besides being compact, such MOTs can be useful in atom interferometry set-ups where different atom clouds with different initial hyperfine states need to be prepared.