Abstract: A precision voltage reference device having a forward biased and reverse biased silicon junctions arranged as a concentric circular annular monolithic structure is described. Selective hardening of the forward biased junction is provided to adjust carrier lifetime in said junction thereby providing a radiation hardened device. The selective hardening is provided by implanting non-dopant species to induce a predetermined amount of lattice damage at the forward biased junction. This arrangement permits both the forward biased junction and the reverse biased junction to be fabricated on a common substrate.

Abstract: A system for exercising paralyzed human limbs by functional electrical stimulation. The system utilizes simple analog devices including a reference signal generator, a position sensor and an error signal generator. The error signal is integrated to produce a stimulation driving signal for application to stimulation electrodes mounted on the limb. In the disclosed embodiment the paralyzed person may be seated in an exercise chair. The chair is equipped with a pair of loading assemblies which may be attached to the legs of the person so as to yieldingly resist stimulated movement thereof.