My kids helped me look at these.
100 disc capacitors in a bag.
In my attempt just to get a supply
of electronic parts so I can build
some circuits here and there, I
My kids helped me look at these.
100 disc capacitors in a bag.
In my attempt just to get a supply
of electronic parts so I can build
some circuits here and there, I
came upon this bag in the "you know
what" store.
I found some values, that when put
together, give me the capacitance
I need for the final stage of the 13.560
MHz "Big Talker" transmitter.
What is funny is that, out of the 100
caps, about 50 or 60 just say "10"
on the front, which translates to
10 pF in my book. Then there are another
10 or so that say "1" on the front, with
a line under them. Looks like 1 pF to me.
1 pF???? What do you do with 1 pF?
Then there were 3 blue disc that were very
pretty, but had no numbers. I don't have
a cap checker, but I know they could be
figured out.
The PI net out on the "Big Talker" needs 2
270 pF caps. I found about 5 caps that
are marked "221," which in my book means
220 pF. I plan to combine them with caps
that say "68" which translates to me as 68 pF.
So each cap that should be 270 pF will be
288 pF for now. I will replace them later.
I just thought I would report on the grab bag
from you know where.
I also don't know how stable these caps are
regarding circuit "warmup," heat, etc.
Oh well, that's my report.
Back to you Chet.
Bruce, DRS2
Your cap summary sounded right to my spiral-ears, and I have a few things to add.
When I ordered parts for Big Talker there were no 270pF in the catalog, so I got a couple 221 (220pF) plus a couple 50pF, and created extra room on the output section for all four caps.
I later wondered if maybe I should have ordered the RF MICA capacitors like the ones in the LPB final filter, but I'm guessing that at the low power of the Big Talker the more common caps will be o.k.
You know what you're doing. Boy, does that ever help.
Yup! Thank you for your input.
I plan to make the band pass
(pass band?) filter later.
Later in the summer, I plan to
make a pilgrimage out to an
electronic store that I can't
normally get to. I'm know they will have
more chokes. I also want to
build a new Rf circuit for the
carrier current transmitter,
with toroids, so it won't throw
out as much RF field as the
present one does.
Best Wishes,
Bruce, DRS2