Optical Isolators Figure 3.12 shows an optical isolator. The optical isolator (called an optoiso- lator or optocoupler) houses an LED and a phototransistor in a package like an IC. The optical isolator is sealed—there is no way to break the light path. The optical isolator is not used to detect mechanical motion, but to provide electrical isolation between two electrical circuits. A common use for optical isolators is to isolate a high-voltage circuit from the microprocessor that con- trols it. MIDI (Musical Instrument Digital Interface) uses optical isolation to connect synthesizers, computers, and other electronic musical instruments. In this application, the use of optical isolators prevents problems caused by different ground potentials. Sensors 67 Figure 3.12 Optoisolator. Figure 3.12 shows how an optoisolator can be used to pass signals from one system to another
Page xiii: Minor change to AC Power Supply Unit pre- Pages 12, 48, 102: SYSMAC-CPT information added. caution. Page 15: Changed the specifications for the analog con- Page xv: Changes made to crimp terminal wiring and trols. Pulse output added. forced set/reset precautions. Page 18, 19, 32, 34, 35, 39, 53 : Changed the wording of Page 2: Information on sink-type and source-type tran- the caution. sistor output models added. Pulse output function Page 35: Information for 24-VDC Power Supply rewrit- information added
A brief of storage, treated beef counts were 4.5 logs summary of bacteriocins is presented in less than control samples. Schilling et al. Table 14.4. (2003) showed that blade-tenderized beef Of a variety of bacteriocins discovered, treated with HDS had lower standard plate only nisin (commercially available as counts (0.5 log difference) compared to con- Nisaplin®) is on the Generally Recognized as trols after 14 days of storage. On the other Safe (GRAS) list as a direct food additive hand, Moeller et al. (1999) found no signifi- approved by the U.S. FDA (Siragusa et al. cant difference in aerobic plate counts and 1999). This heat-stable, easily digestible coliform counts between explosive HDS- bacteriocin is especially effective for control 270 Chapter 14 Table 14.4. Summary of bacteriocins and their producing bacteria
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