. The Bell System technical journal . Fig. 11 — Direct Reading Recorder measured on their rorrespf)nding bridges. In the operation of therecorder, a period of about 20 seconds is allowed by the commutatorto balance each bridge thus completing a cycle every 60 seconds. The recorder is equipped with two pens one of which is associatedwith the slide wire of the dry bulb i)ridge thus recording the drybulb temperature, while the other pen is associated with the humidity SYSTEM TECHNICAL 7;m— ._ a- :... tl . I .5 -T ■i 1—t- 95 •> 100 fMP I0E6 FIVMR. ^ RELATIVE >• MUMiniT^c 1 4
. The Bell System technical journal . Fig. 11 — Direct Reading Recorder measured on their rorrespf)nding bridges. In the operation of therecorder, a period of about 20 seconds is allowed by the commutatorto balance each bridge thus completing a cycle every 60 seconds. The recorder is equipped with two pens one of which is associatedwith the slide wire of the dry bulb i)ridge thus recording the drybulb temperature, while the other pen is associated with the humidity SYSTEM TECHNICAL 7;m— ._ a- :... tl . I .5 -T ■i 1—t- 95 •> 100 fMP I0E6 FIVMR. ^ RELATIVE >• MUMiniT^c 1 4 Fig. 12—Temperature and Relative Humidity in a Humidity Room I iiUMinny rhcordi-rs 235. Fig. 13—Outdoor Temperature and Relative Humidity 2S6 BELL SYSTEM TECHNICAL JOURNAL bridge, thus recording the values of humidity directly. Inasmuch assuccessive operations of the recorder consist in the restoration of thebalance of each bridge, if different from the last position of balance, itis evident that the pens will trace continuousK- the \arialions oftemperature and relali\e humiility. A recorder of this type with its associated wind tunnel mechanismhas been used for some time to record the conditions in a laboratoryhumidity room. The temperature record gi\en by this recorder isaccurate to ±°F. as in the case of the difference recorder. Tlioaccuracy of the humidity record differs for various points on the scale,depending upon the values chosen for certain resistances in the the recorder is adjusted for very close accuracy (±3-2% relati\ehumidity) for relali\e humidities above 90%, the accuracy for lowervalues of humidity decreases until at 50% the maximu
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
