Subject:
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Re: To all sensor developers, why use voltage drive ?
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Sat, 3 Mar 2001 01:33:10 GMT
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Viewed:
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1457 times
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Stef Mientki <s.mientki@ids.kun.nl> wrote in message
news:3AA01C30.6FFBA740@ids.kun.nl...
> Hi,
>
> Why is everyone using a voltage driven cirquit when devolping a RCX
sensor-cirquit, while the RCX sense input is in fact a current sensing input
?
What the RCX measures is voltage. It has a 10k pull up to 5V, but it
measures voltage. If you force a voltage on the input using a low enough
impedance you will see that it measures that voltage. Your current based
circuits are compensating for the diodes non linear behavior. Also the
LM324 is a pretty poor opamp.
The reason for the opamp with a 1k resistor circuit is that it is simple.
Just like the diodes in place of FETS. Great linearity is often not that
necessary. My projects are driven mostly by solutions that can come from
the Radio Shack retail store and can be built without surface mount
technology. It is a compromise.
Great web page.
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Message has 1 Reply:
Message is in Reply To:
 | | To all sensor developers, why use voltage drive ?
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| Hi, Why is everyone using a voltage driven cirquit when devolping a RCX sensor-cirquit, while the RCX sense input is in fact a current sensing input ? Ok, I admit, until short I also copied the schematic everyone is using. But I now think the (...) (24 years ago, 2-Mar-01, to lugnet.robotics.rcx)
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