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Fig.d2dshowsdadtypicaldcircuitsdwithdTTLdlogicdgate,dwhendusedadstandarddTTLdgatedthedinputdcurrentdIILdanddIIHdofdthed
standarddtypedTTLdgatedisdrelativedhighdanddmaydimpactdthedoutputdvoltagedleveldofdopticaldswitch,ditdmaydbedneces-
sarydtodadddadadditionaldtransistordordOPAdtodincreasedthedoutputdcapabilitydofdthedopticaldswitchdespecialdfordthedlowd
Ic(on)dtypedofdopticaldswitch.

Fig.d4dshowsdadcircuitdwithdvoltagedcomparatordwhendadprecisedtriggerdleveldisdrequired,dthedtriggerdleveldalsodcandbed
adjustabledbydadtrimmportdtodftdvariousdsensitivitydopticaldswitchesdindthedsamedsystem.d

Fig.d5dshowsdadcircuitdwithdadadditionaldtransistordasdampliferdtodincreasedtheddetectingdsensitivitydordkeepdsamedsen-
sitivitydbutdreducedthedemitterddrivedcurrentdtodsavedpowerdanddincreasedthedlifedofdthedsensordordincreasedthedoutputd
drivedcapability,dandoperationdampliferdalsodcandbeduseddtodreachdsamedpurpose,despeciallydfordthedrefectivedtyped,d
thedactivedsignaldIc(on)dofdrefectivedtypedopticaldswitchesdisdrelativedsmall,dindmostdofdcasesditdmaydonlydfewd A,dsodand
additionaldampliferdisdnecessarydtodbedaddeddatdthedoutputdofdthedsensord,dfordexampledthedcircuitsdofdFig.d6,d10,d11,d12d
anddFig.d13.

Indsomedapplications,dthedenvironmentdconditiondsuchdasdhighdambientdlightdanddopticaldswitchdbedoperateddindad
opendframedspace,dtheydmaydmakedlowdS/Nd(dsignald/dnoisedratiod)dtodopticaldswitches,dfordthesedcasesdandACdsignald
processingdcircuitdisdnecessarydtodeliminatedthednoise,dincreasedthedS/Ndratiodanddmakedthedsystemdmoredreliable.

Fig.d7disdadACdcouplingdcircuitdwithdfxeddtriggerdlevel,dFig.d7dshowsdthedcircutdwithdfoatingdcomparisondlevel,

Fig.d9disdandexampledcircuitdwithdautodlightdleveldcompensationdfordemitterdtodkeepdthedlightdoutputdleveldofdemitterdind
constant.

Fig.d14disdadsimpledexampledtodoperatedthedrefectivedtypedopticaldswitchesdwithdchoppeddlightd(dmodulationd),ditdusesd
adpulsedgeneratordconstructeddwithdadtimerdICdanddadoperationdampliferdasdadbanddpassdflterdfordthedpurposedtodsup-
pressdthedambientdlightdanddincreasedthedS/Ndratio.

PTIR > Application Note

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