[sdiy] Level Translation

[Tim Ressel]

D'oh!  Duh! 

This is why engineers have flat foreheads ... from
whacking them with their hands when the obvious is
seen. Look up an MC1488. Its a TTL to RS232 level
translator, and it has pretty much the SG circuit in
it. In fact, one could just use that IC to do the
level translation. Since I have 4 outputs to shift,
and the MC1488 is a quad, I think I'll just use it.

Thanks to all who answered my query.

--TR


--- Scott Gravenhorst <music.maker at gte.net> wrote:
> Ok, time for the list to give Scott another lesson
> in basic
> electronics, but here goes:
> 
> home1.gte.net/res0658s/levtrans.gif
> 
> Is my idea (that I still have not tested), part of
> another
> design.  My original need is to translate TTL levels
> to +/- 8
> volts.
> 
> The way I think it _should_ work is this:
> 
> Supplies: +v = 10 volts, -v is -10 volts.
> 
> Since the input is expected to be the output of a
> CMOS gate,
> I'm assuming it's valid levels to be 0 or 15 volts
> and not
> much inbetween matters.
> 
> When the input is 0 volts, the input NPN is off and
> the it's
> collector should be at or near 10 volts.  This
> should cause
> the PNP to turn on which should in turn cause the
> output NPN
> to turn on.  The output NPN's collector should then
> be at or
> near -v or -10 volts.
> 
> When the input is 15 volts, the input NPN is turned
> on and
> it's collector should be close to ground.  This
> should cause
> the PNP to be off, which will then not supply base
> current to
> the output NPN, turning if off.  This allows the
> output NPN's
> collector to rise to near +v causing a +10 volt
> output.
> 
> 
> Ok, I'm here to learn, so tear me apart.
> 
> If this solution is totally noob, so be it, but I am
> also
> interested in a solution to this.  (I'd rather not
> use op-amps).
>  
> 
> Tim Ressel <madhun2001 at yahoo.com> wrote:
> >Yo, Can you spare a cup of neurons? I'm all out...
> >
> >This is something I've never been good at: I have a
> >cmos gate putting out a 0-15V signal, and I need to
> >translate that to +/-10V. I just can't seem to wrap
> my
> >move-addled brain around this today.
> >
> >TIA
> >
> >--TR
> >
> >
> >__________________________________________________
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>
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> -- Scott Gravenhorst | LegoManiac / Lego Trains /
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