A driver circuit is used for driving a plurality of switch elements connected between a power supply terminal and a common terminal. In one embodiment of the invention, the computing device receives input requesting the computing device to begin operation and executes a set of one or more instructions stored in a non-volatile memory. When aiming the weapon, a user will look through the tubular member towards the target and for proper alignment with respect to the target, will maneuver the weapon until the circle-like images are concentrically disposed. The tongue cleaning electrode enables a current flow into a user’s tongue during operation.