> Hi,
> Yup sorry.
>
>
>
> On Wed, 13 Oct 2004 16:06:19 +1000, David Duffy
> <davidKILLspamaudiovisualdevices.com.au> wrote:
> >
> >
> > Wan Zulhelmi Wan Ahmad Kamar wrote:
> >
> > >Hi,
> > >I've got a problem with my amplifier circuit. It's suppose to be a
> > >simple 1000x amplification circuit, using LM833.
> > >
> > >Instead of amplifying, my circuit is actually 'de-amplify'. By
> > >observation, when i put a signal of around 5 V, the output from the
> > >first amplifier is around 1V, and around few mV at the output of the
> > >second amplifier.
> > >
> > >I was trying to look at the datasheet for some clue, but fail to do so.
> > >
> > >I tried before with a LF356 circuit to amplify, and it works well. So,
> > >i can't find any reason why an op amp doesn't amplify.
> > >
> > >If someone could help, that would be greatly appreciated.
> > >
> > >
> >
> > Got a circuit we can look at?
> > David...
> > _______________________________________________
> > http://www.piclist.com
> > View/change your membership options at
> > mailman.mit.edu/mailman/listinfo/piclist
> >
>
>
>

> At 12:42 AM 10/13/2004, Wan Zulhelmi Wan Ahmad Kamar wrote:
>
> >Hi,
> >I've got a problem with my amplifier circuit. It's suppose to be a
> >simple 1000x amplification circuit, using LM833.
>
> 1000x DC amplification?  Input offset errors could be eating you alive.
>
> Looking at the specs, the LF356 also has 10 or 5 mV offset, but it's input
> bias current is way lower.
>
> Check the effect that the input bias current would have in your circuit.
> ecircuitcenter.com/Circuits/op_ibias/op_ibias.htm
>
>
>
> _______________________________________________
> http://www.piclist.com
> View/change your membership options at
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>

> Wan Zulhelmi Wan Ahmad Kamar wrote:
>
> >Hi,
> >The file. Thanks
> >
> >
>
> What frequency are you trying to use?
> The 100pF seems way to low with the 10K resistor.
>
>
> David...
> _______________________________________________
> http://www.piclist.com
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

>
>I was trying to look at the datasheet for some clue, but fail to do so.
>
>I tried before with a LF356 circuit to amplify, and it works well. So,
>i can't find any reason why an op amp doesn't amplify.
>
>If someone could help, that would be greatly appreciated.
>
>>From wan
>spamBeGonewanzulhelmispamBeGonegmail.com
>_______________________________________________
>http://www.piclist.com
>View/change your membership options at
>http://mailman.mit.edu/mailman/listinfo/piclist

>-----Original Message-----
>From: TakeThisOuTpiclist-bouncesEraseMEspam_OUTmit.edu [RemoveMEpiclist-bouncesTakeThisOuTmit.edu]
>On Behalf Of Dave VanHorn
>Sent: 13 October 2004 15:23
>To: Microcontroller discussion list - Public.; Microcontroller
>discussion list - Public.
>Subject: Re: [EE] Amplifier Circuit
>
>
>At 01:55 AM 10/13/2004, Wan Zulhelmi Wan Ahmad Kamar wrote:
>
>>Hi,
>>I am trying to send a 40 kHz signal through a transducer. At the
>>receiver, i am using a bandpass and an amplifier
>configuration(amplying
>>at 1000x as the signal receive through the transducer is
>really small).
>>
>>Is it really too small?
>
>
>What are the slew rates of these amplifiers?
>It's possible that the chip you're using can't get that much
>gain at 40 kHz.

> Is a bandpass filter necessary?  Isn't the xducer simply a bandpass filter
> itself?
>
> Loose the bandpass filter and loose some attenuation?
>
> Bill
>
> ps  First post on here after a few years absence, so be gentle if problems
> please.
>
>
>
>

>Hi,
>It's quite true that the transducer is already a bandpass filter. But,
>then again, the filter is just to be safe there. No harm in doing
>that,(except that maybe it adds up more gain.. argh).
>
>But, looking back at the circuit again. There is nothing wrong with
>it.. theoritically, right. I was just hoping that i need to play
>around more with it.
>
>I was hoping that maybe my connection is loose, or the values are
>wrong, rather than my circuit is wrong.
>
>

> At 07:24 PM 10/13/2004, RemoveMERichard.Prosserspam_OUTKILLspampowerware.com wrote:
>
> >To state the obvious - Power supply ON.?
> >
> >And how are the DC voltages around the circuit? Are they as expected or
> >jammed against one or the other rails?
>
> When a prototype doesn't work, there are only three possibilities:
>
> 1: It's designed wrong. Check your assumptions and math.
> 2: It's built wrong. Check your connections and voltages.
> 3: It's actually working, check your test setup.
>
>
>
>
> _______________________________________________
> http://www.piclist.com
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

>
> Hi guys,
> Thanks so much for all the input.
>
> I have checked my circuit, and just found one silly mistake.
> The Channel 2 on the CRO is not working. When i test to look at the DC
> output of my power supply, there were just some bunch of junk.
> Damn the CRO.
>
> Now, my circuit works great.
>
> And the 1000pF works great.
>
> Thanks.
>
> On Wed, 13 Oct 2004 18:39:16 -0500, Dave VanHorn <RemoveMEdvanhornTakeThisOuTspamdvanhorn.org> wrote:
> > At 07:24 PM 10/13/2004, EraseMERichard.ProsserspamspamBeGonepowerware.com wrote:
> >
> > >To state the obvious - Power supply ON.?
> > >
> > >And how are the DC voltages around the circuit? Are they as expected or
> > >jammed against one or the other rails?
> >
> > When a prototype doesn't work, there are only three possibilities:
> >
> > 1: It's designed wrong. Check your assumptions and math.
> > 2: It's built wrong. Check your connections and voltages.
> > 3: It's actually working, check your test setup.
> >
> >
> >
> >
> > _______________________________________________
> > http://www.piclist.com
> > View/change your membership options at
> > mailman.mit.edu/mailman/listinfo/piclist
> >
> _______________________________________________
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