a torpedo ejects lead weight at the conclusion of a practice run and is bed to the surface for recovery and reuse . a squib is initiated to release the weight by a control circuit which is actuated when the torpedo engine stops . an appropriately interconnected transistor and field effect transistor respond to built - up charges on three charge storage circuits to assure the proper initiation of the squib when the torpedo stops running . the stored energy thus is brought into effect to assure reliable separation and avoids the problems otherwise associated with conventional electromechanical relays .