13 Oct
2008
13 Oct
'08
11:48 a.m.
On Mon, Oct 13, 2008 at 09:46:01AM -0700, Chuck Guzis wrote:
On 13 Oct 2008 at 4:08, Ethan Dicks wrote:
I can entirely believe that. What I'm wondering is if the original
article should have read 2200pF.
The schematic shows the horizontal sync coupled
to a gate via a "2200 mf"
non-polarized cap. I don't know that I have any disc or ceramic caps that
large lying around. The output of that gate (which NORs the inverted
vertical sync with the massaged horizontal sync) feeds unto a "47mf"
tantalum cap (then pulled down to ground by a diode, and wire-ored to
inverted video out/composite out via a 470 Ohm resistor). I have 47uF caps,
but that seems pretty large to me.
That 2200mf is off by at least 3 orders of magnitude. 0.22 uF is
probably more like it. The 47 uF might be okay, but I suspect that
4.7 uF may also work just fine. (But I don't have your circuit, so
it's really difficult to say for certain).
Agreed.
It's been a long time since I wired up one of
these, but ISTR that I
didn't find component values to be very critical.
Glad to hear it. I'm going to build the first version on a proto board
so it will be easy to swap out caps.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 13-Oct-2008 at 18:40 Z
South Pole Station
PSC 468 Box 400 Temp -53.7 F (-47.6 C) Windchill -84.3 F (-64.6 C)
APO AP 96598 Wind 9.9 kts Grid 52 Barometer 668.5 mb (11065 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html