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Unread 04-01-2007, 15:58
charrisTTI charrisTTI is offline
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Re: Set Default Digital inputs to Low? How? bad Analog value?

Check out this application note.

http://www.optekinc.com/pdf/App_Note_213.pdf

See figure 1 and figure 3.

The collector current of the phototransistor is relatively low.

The OPB606 is 500 uA this can pull down 5V thru a 10k resistor.
The OPB704 is 50 uA this can pull down 5V thru a 100k resistor.

I do not know what the input circuit of your controller looks like, but I would guess that the OPB606 might work with a direct connection as long as pullup is 10k or greater.

The OPB704 will very likely need the circuit shown in figure 3.
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