Andy,
Let us know how you come out.
David
----- Original Message -----
From: Andrew Kunz <RemoveMEakunz
TakeThisOuTTDIPOWER.COM>
To: <PICLISTEraseME
.....MITVMA.MIT.EDU>
Sent: Tuesday, August 08, 2000 7:38 AM
Subject: Re: [EE]: PWM-to-analog voltage
> Thanks, David. The tech hunted around and found some 1N34's in the stock
room.
{Quote hidden}> He's swapping them out now.
>
> Thanks.
>
> Andy
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> David & Lily Covick <
EraseMEdac
WEST.NET> on 08/08/2000 10:27:08 AM
>
> Please respond to pic microcontroller discussion list
<RemoveMEPICLISTEraseME
EraseMEMITVMA.MIT.EDU>
{Quote hidden}>
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>
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> To:
RemoveMEPICLISTspam_OUT
KILLspamMITVMA.MIT.EDU
>
> cc: (bcc: Andrew Kunz/TDI_NOTES)
>
>
>
> Subject: Re: [EE]: PWM-to-analog voltage
>
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> Andy,
>
> The diodes are very important....you are correct. If you do not use
1N34's
> or a germanium diode substitute, then it will not work
properly......believe
{Quote hidden}> it or not :)
>
> I know the circuit works fine and I've shared it with others with
> success....
>
> Keep on trying. Possibly it will work with silicon with
> modification.....but the 1N34's are needed for low forward drop....this is
> what is killing the operation.
>
> I think another alternative is a 1N270.....try looking up that one.
>
> David
>
>
> ----- Original Message -----
> From: Andrew Kunz <
RemoveMEakunzTakeThisOuT
spamTDIPOWER.COM>
> To: <
EraseMEPICLISTspam
spamBeGoneMITVMA.MIT.EDU>
> Sent: Tuesday, August 08, 2000 7:15 AM
> Subject: Re: [EE]: PWM-to-analog voltage
>
>
> > >I designed this little circuit a few months ago using SPICE.
> > >Just vary the PWM and you are home free. You don't need any external
> > >negative voltage!! It produces negative voltage on its own using a
> positive
> > >voltage in a charge pumping type method off the PIC PWM.
> > >
> > >The attached virus free jpg schematic will fill you in.
> >
> > Tried it. Looking at it with a scope, I see a standard "ac-coupled"
> waveform
> > from the PWM output pin relative to GND. If I disconnect the diode/cap
> circuit,
> > the waveform has nice square form.
> >
> > I didn't have any 1N34's so we stuck in a 1N4004. Right now I'm
searching
{Quote hidden}
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