Abstract: An accelerator for a projectile includes a coil; an H-bridge coupled to the coil with four relays S1-S4, and a controller to control current flow in the coil, wherein when relays S1 and S4 are on and relays S2 and S3 are off, current goes through the coil in one direction, and when the states of the relays are switched, current direction reverses, wherein switching the current direction ensures that the projectile has a positive acceleration.