An active armor system which includes an outer and an inner armor layer with a medial space between these inner and outer armor layers layer. One or more relatively small shaped charges are positioned on the inner armor layer in the medial space. If the outer armor layer is struck by a projectile having a shaped charge, one or more of the small shaped charges positioned in the medial space near where the projectile has struck the outer armor layer are detonated. The small shaped charges in the medial space are positioned so that when they are detonated, their jets will tend to intersect with or be oppositely directed to the jet from the shaped charge on the projectile so as to disrupt the jet from the projectile and prevent the penetration of the inner armor layer. The small shaped charges in the medial space may be detonated by an electrical current produced when a piezoelectric material, an electrostrictive material, or a magnetostrictive material in the outer armor layer is struck by the projectile. Alternatively, the small shaped charges in the medial space may be detonated as a result of being contacted by the jet of the detonated shaped charge on the projectile. The small shaped charges in the medial space may be used in conjunction with the electrical or magnetic fields described in the related applications cited above to disrupt the jet of the shaped charge on the projectile.