A power source apparatus and a system incorporating said power source for medical capsules are disclosed. Embodiments of the present invention allow the medical capsule to enable/disable electrical power supplied to a sub system in the capsule device without special tools and/or skills after the medical capsule is manufactured. In one embodiment the power source apparatus comprises a plunger responsive to a magnetic field a spring to interact with the plunger a battery and a control piece. The plunger is moved between first and second positions according to a magnetic field applied externally. Accordingly the control piece enables or disables the power depending on the plunger positions. In another embodiment a capsule system uses an electrical interconnect with pressure contacts between the power source and the capsule sub system connecting the second circuit board to the power output nodes.
