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Re: Yes, Virginia, there is a LFO!

1999-11-29 by The Old Crow

On Mon, 29 Nov 1999 Elhardt@... wrote:

> Now that I see the back of the LFO and can see that it uses a dual color LED 
> with only two leads, I can't understand that $5.40 cost for LED and cable 
> assembly.

  There is also the polarity-reversing LED drive circuit to consider.
Granted, a 74LS00 will suffice, or some comparator/opamp output that
slopes between + and - wrt gnd, but it is an added cost.  Then there is
the circuit that interfaces the LED drive to the LFO itself.  It might be
trivial or it might be a bit more complicated--need to see the schem.

  I'm curious as to what the LED jumper row is for.

  I noticed a tempco on some differential pair.  Guess that is needed to
make those 10-minute cycles stay 10 minutes. :)

  --Crow

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