a microprocessor connected to the battery through a regulator to obtain {TAIL ~ a suitable DC voltage}, the power supply switch and {HEAD ~ the illumination switch} 
a microprocessor connected to the battery through a regulator to obtain { TAIL ~ a suitable DC voltage } , the power supply switch and { HEAD ~ the illumination switch }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD