A micropower bipolar implantable stimulator has been developed and tes
ted for long-term (four weeks-six months) use in experiments involving
the stimulation of denervated skeletal muscle. Implantable stimulator
s are typically operated from a single lithium battery at 3 V. After t
he first week of denervation, stimulation of denervated muscles of rat
s requires voltages in the range of 6-12 V. The stimulator described c
an deliver voltages up to 15 V, with variable pulsewidth, frequency an
d duty cycle. All stimulation parameters are set prior to implantation
by selection of appropriate resistors and capacitors. Each primary fa
ilure mode for implantable stimulators is addressed. Longterm reliabil
ity rates in excess of 95% are achievable if the construction details
are followed closely. Methods for battery power management, circuit co
mponent selection, electrode construction and encapsulation are descri
bed in detail. This device is not intended for use in humans.