28 A
ANALYTICAL
CHEMISTRY
INSTRUMENTATION finish, knockouts provided, tamperproof, locking means provided. At a price of approximately $35, this reliable control unit offers many control possibilities in instrumentation at an attractively low cost figure. Miniature Precision
the sealed cells of ο tt9MIWS!|IS^|Bip8P î pWW} i "'«rîtical concentrations of a gaseous component to be recorded a n d to control industrial processes through the Baird Associates Plant Stream Analyzer. This sensitive, accurate, reliable instrument has proved its worth in control applications involving: η-Butane in methane, ethane, propane, iso-butane, CO, and C 0 2 ; methane in natural and manufactured gas blends; carbon dioxide in expired air; acetylene in 14-component mixture; methane in 14-component mixture; carbon dioxide in 7-component mixture; hydrogen cyanide in 8-component mixture; ammonia in 7-component mixture; acetone in air; acetylene in hydrogen cyanide. Your process control may benefit by use o f the Baird Associates Plant Stream Analyzer. Bulletin 36 gives detailed information; ask us about the use of this instrument in your control problems.
Baird Associates, INDUSTRIAL 3 3 UNIVERSITY ROAD
Inc.
PHYSICISTS CAMBRIDGE
38,
MASS.
Potentiometers
Burlingame Associates also announce a complete new line of miniature pre cision potentiometers manufactured by the Standard Electronics Mfg. Co., Los Angeles. While the basic applica tions of these devices include guided missiles, telemetering, computers, and radar firing control, they are suited for any applications requiring a miniature precision potentiometer. The Type F potentiometer is available in the minimal dimensions of 1 X 1 χ 0.4 inch of rectangular form and is unique in both mechanical design and oper ation. The winding form lies length wise in the case and is a rhombus in cross section with the contact wiper moving along one of the obtuse angled edges. The wiper is moved by a lead screw which can have as little as three turns (1080°) for full travel or as many as 32 turns (11,520°) for full travel. Any units which have the same type lead screw can be ganged and the windings may be tapped. These units are available in resistance values from 100 to 250,000 ohms with power ratings from 0.25 to 2 watts. Depending upon the range, the maximal length of the device can be 3.5 inches and a maximal width of 0.625 inch. The Type SR is indeed miniature. It is 5/s inch in diameter and 27/32 inch long over the terminals. It is rated at 0.5 watt and can be furnished in resistance values from 100 to 50,000 ohms. In general, these units are designed to operate over a temperature range of — 67° to +165° F., but in some designs alkyd plastic cases can be supplied which extend the upper range to +300° F. Resistance tolerance is normally 5%, but can be supplied to 0.5%. Linearity tolerances are normally 1%, but 0.1% can be furnished. No infor mation is available on the torque re quirements and it is to be inferred, perhaps, that these devices are not com petitive with the micro-torque type such as the Giannini version. Their unique construction and small size should fur nish another useful tool.
