Subject:
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Re: LEGO light sensor schematic
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 4 May 1999 23:01:18 GMT
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Viewed:
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948 times
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Well if anybody still cares, I think the LEGO light sensor circuit is 100%
correct now. The sensor is a phototransistor. Looking at the circuit implies
a interesting side effect. If you shine a very bright light (ie laser
pointer) into the phototransistor it will take current away from the LED and
make it go off. I tried it and it works. It is of no real value, but it does
further confirm things. Thanks for all your help fixing it up.
http://www.plazaearth.com/usr/gasperi/lego.htm
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Message has 1 Reply:
 | | Re: LEGO light sensor schematic
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| (...) Mike, Could it be that transistor 15 (I think), the one that is configured as a diode whose emitter is tied to the emitter on the output of the OpAmp potentially be some kind of non-linear negative feedback loop? Maybe to prevent oscillation (...) (25 years ago, 5-May-99, to lugnet.robotics)
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Message is in Reply To:
| | Re: LEGO light sensor schematic
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| Dennis Clark wrote in message ... (...) Your right. It just can't be the way it is drawn. I think it must be a photo transistor. Usually photo diodes are not as sensitive as photo transistors either. I'll touch up the circuit and see if it looks (...) (25 years ago, 4-May-99, to lugnet.robotics)
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