[Coco] It's a small win, but a win nonetheless

RETRO Innovations go4retro at go4retro.com
Sat Mar 11 12:36:55 EST 2017


On 3/11/2017 4:03 AM, Gene Heskett wrote:
> Jim, how big is the coupling capacitor?
I tried .1uF, 1uF, and 47uF (yeah, big jump, but I was getting desperate)
> I'd use at least a .05 uf in a
> high impedance circuit, or a .5uf mylar in the lower impedance
> transistor circuit. The p-p measurement you started with, .7 volts,
> should not be reduced by the capacitor, only its dc operating point.  If
> its that reduced by the capacitor, the capacitor is too small. Multiply
> its capacitance by 5 to 10 in that case.
Let me retry the tests today and take pics of the scope, as I tried so 
many things last night I forget what showed what.
>
> Also I don't recall if you specified the comparators jedec number.  There
> are comparators available whose inputs can include the -(ground) rail as
> opposed to needing a ttl level bias, or half the + rail bias at both
> inputs.
Hmm, I'll have to check if this comparator can use ground as one of the 
inputs.
>
> Cheers, Gene Heskett


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