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Author: Jeroen BellemanJeroen Belleman
Date: Mar 31, 2008 23:45
Joerg wrote:
> While contemplating a new design I was looking around for tapped
> inductors and 455kHz IF filters which also can be used as such. Got a
> sticker shock. Even at quantities they can't be had under 75c. Ouch!
> Also, not many brands. Digikey doesn't have any, Mouser only carries one
> (Xicom).
>
> Are LC IF filters finally going lalaland? I remember them to be really
> cheap. They had to, because even a $10 radio contained half a dozen of
> those.
>
You do know Neosid, I presume? It's admittedly been ages since I
last bought filter coils from them, and I don't remember them as
cheap.
Jeroen Belleman
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Author: JasonJason
Date: Mar 31, 2008 23:03
I have built two identical RC circuits that seem to work perfect. But
I have connected the output signal from one RC circuit (A) into the
voltage input of the other RC circuit (B) to try & create a timing
signal with a "gate time" or delay. ie. One pulse every second from
circuit B and circuit A turning circuit B on for 5 seconds then off
for 5 seconds.
When I check these circuits with the DMM for frequency & duty cycle
they're fine until I connect them together. When connected together
the DMM gives some erratic readings (during off state of circuit A I
think?... not sure). I tried a diode on circuit A output incase there
was some sort of signal coming back from circuit B but didn't seem to
effect the readings. The voltage levels out of circuit A seem to meet
the specifications for minimum...
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4 Comments |
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Author: Paul Hovnanian P.E.Paul Hovnanian P.E.
Date: Mar 31, 2008 17:46
Two Radical Arab Terrorists boarded a flight out of London . One
took a window seat and the other sat next to him in the middle seat...
Just before takeoff, a U.S. Marine sat down in the aisle seat. After
takeoff, the Marine kicked his shoes off, wiggled his toes and was
settling
in when the Arab in the window seat said, "I need to get up and get a
coke."
"Don't get up," said the Marine, "I'm in the aisle seat, "I'll get it
for you."
As soon as he left, one of the Arabs picked up the Marines shoe and spat
in it.
When the Marine returned with the coke, the other Arab said, "That
looks good, I'd really like one, too."
Again, the Marine obligingly went to fetch
it.
While he was gone the other Arab picked up the Marines other shoe
and spat in it.
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2 Comments |
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Author: blankoblanko
Date: Mar 31, 2008 17:36
The speaker that I am currently using produces ~65dB at 3kHz 1 meter
away:
http://www.cui.com/pdffiles/CDMG16008-03.pdf
I have been searching around for speakers that will allow me to
produce > 70 dBA at ~3kHz measured 1 meter away, fully enclosed in our
plastics.
I am going to need a beefier speaker - does anyone have any
recommendations?
Thank you very much.
-Mike
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Author: Jon SlaughterJon Slaughter
Date: Mar 31, 2008 16:53
To measure the inductance of an inductor all I really have to do is compute
the reactance? i.e., put a sin wave in at voltage v and compare its output
voltage? Knowing how much it attenuated it should give me L? Well, I guess
its harder since one has to deal with the external resistances? Will using
an op amp for drive work and just use a "high freq signal(or sweep through
some range and include a current limiter? (obviously one would measure at
several frequencies to get a good picture)
Thanks,
Jon
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