Archive of the former Yahoo!Groups mailing list: MOTM
Subject: Re: Yes
From: The Old Crow <oldcrow@...
On Mon, 29 Nov 1999 Elhardt@...
> 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
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. :)