ChrisOfBristol
Member
I have an infrared (IR) position detector which consists of an IR LED and an IR photodiode with a rotating slotted disk between them - rather like in a computer mouse. I want the output to be permanently on, which should enable me to simplify the circuit, reducing the number of wires and components and increasing reliability.
I believe that the photodiode should be reverse biased, with the result that little current flows in (IR) darkness and more flows in light. It seems to me that this is equivalent to saying that there is high 'off' resistance which changes to a low 'on' resistance. I think the off resistance is very high (100s of KOhms), what would be the on resistance? I can test this, but would value your opinion.
I aim to dump the IR LED and replace the IR photodiode with a resistor which will simulate the on condition. Is this practical?
I believe that the photodiode should be reverse biased, with the result that little current flows in (IR) darkness and more flows in light. It seems to me that this is equivalent to saying that there is high 'off' resistance which changes to a low 'on' resistance. I think the off resistance is very high (100s of KOhms), what would be the on resistance? I can test this, but would value your opinion.
I aim to dump the IR LED and replace the IR photodiode with a resistor which will simulate the on condition. Is this practical?
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