The temperature sensor and {HEAD ~ the passive infrared sensor} are mounted on {TAIL ~ a front electrical lead side} of a vertically positioned PC board, and heat generating electrical components are mounted on an opposite, back component side of the PC board 
The temperature sensor and { HEAD ~ the passive infrared sensor } are mounted on { TAIL ~ a front electrical lead side } of a vertically positioned PC board , and heat generating electrical components are mounted on an opposite , back component side of the PC board
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH