Can''t get op-amp (LM358) to work.
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Posts: 46,084
Hi Subhrajit,
If your LM358 is powered from a 5 volt supply, then an input level
above 4 volts is beyond its "common mode input range". Could that be
your difficulty?
-- Tracy
>Hello,
>
>I am new to this embedded control stuff, and I am working on my own.
>And I have this problem.... I am working with the Industrial control
>book, and I am trying to implement the 1st ckt in chapter 2.
>
>The LM358 has it's input tied to a phototransistor whose voltage is
>switching between 4.77 and 4.13 V (measured using multimeter). The
>reference voltage is around 4.52 V. The output of the op-amp remains
>unchanged at around 3.7 V. I tried both the op-amps in the LM358.
>No luck.
>
>Is the chip bad ? Is there something I should try before getting a
>new chip ?
>
>Thanks a lot.
>Subhrajit
>
>
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If your LM358 is powered from a 5 volt supply, then an input level
above 4 volts is beyond its "common mode input range". Could that be
your difficulty?
-- Tracy
>Hello,
>
>I am new to this embedded control stuff, and I am working on my own.
>And I have this problem.... I am working with the Industrial control
>book, and I am trying to implement the 1st ckt in chapter 2.
>
>The LM358 has it's input tied to a phototransistor whose voltage is
>switching between 4.77 and 4.13 V (measured using multimeter). The
>reference voltage is around 4.52 V. The output of the op-amp remains
>unchanged at around 3.7 V. I tried both the op-amps in the LM358.
>No luck.
>
>Is the chip bad ? Is there something I should try before getting a
>new chip ?
>
>Thanks a lot.
>Subhrajit
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the
>Subject and Body of the message will be ignored.
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/