Subject:
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Re: light sensor multiplexer
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Thu, 22 Mar 2001 13:09:46 GMT
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Viewed:
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1888 times
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In lugnet.robotics.rcx, Michael Gasperi writes:
Ok I agree what you say about time constant of your RC
But still by using such low resistance you are wasting power. almost 1.5 mA
is flowing through this 4.7K.
you can keep RC constant and increase R that should improve performance.
what I do is I have 5.2V zener in series with 120Kand 10pF this takes
current of 40MicroAmp.
>
> "Nitin Patil" <gn1721@lycos.com> wrote in message
> news:GAKC9v.F5A@lugnet.com...
>
> > Also what I did not like in your desigh is 4.7K resistor. which changes
> > reading in measure cycle.
>
> With the 0.1uF in parallel with the 4.7K, the voltage on the clock circuit
> is still above the measurement voltage during the normal read interval. It
> doesn't effect the reading because the diodes are reverse biased. The 4.7K
> only comes into play when the power is cut by switching to passive. Then
> the capacitor is discharged by it down to where it would effect the reading,
> but your not reading it then.
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Message has 2 Replies:
 | | Re: light sensor multiplexer
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| "Nitin Patil" <gn1721@lycos.com> wrote in message news:GALoKA.Eto@lugnet.com... (...) mA (...) If you use my simple approach, you need 4.7k and around 0.1uF. You need a low enough resistance to guarantee that the voltage drops to CMOS logic level 0 (...) (24 years ago, 22-Mar-01, to lugnet.robotics.rcx)
| | | Re: light sensor multiplexer
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| hi Nitin, I'm an energy freak to, but I can't follow your reasoning Because I'm building a multiplexer too (probably will be posted next week, so I can make still some changes) and I'm using even lower resistor values then Michael (due to a (...) (24 years ago, 22-Mar-01, to lugnet.robotics.rcx)
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Message is in Reply To:
| | Re: light sensor multiplexer
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| "Nitin Patil" <gn1721@lycos.com> wrote in message news:GAKC9v.F5A@lugnet.com... (...) With the 0.1uF in parallel with the 4.7K, the voltage on the clock circuit is still above the measurement voltage during the normal read interval. It doesn't (...) (24 years ago, 21-Mar-01, to lugnet.robotics.rcx)
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