audio recording on IC -help wanted

[Lostgallifreyan]

"John A" <nospam@yahoo.co.uk> wrote in
news:466689ea$0$8744$ed2619ec@ptn-nntp-reader02.plus.net:

You cannot buy variable capacitors with these values, but you could
make up or purchase an arrangement of switches and fixed capacitors
quite cheaply which a) would be the next best thing and b) would
directly address your "how do you measure the capacitance" question.
Commercially they are called Capacitance Substitution Boxes or
Capacitance DecadeBoxes . They're not infinitely variable, of course,
but are finitely practical!

Nice. I'm not sure that's what the OP wanted, (more likely a single
continuous control of something), but if this switched-cap box were built
to 1 nF resolution, for $40 extra or so, you can add a variable capacitor
shown on the page David linked to: http://www.stormwise.com/page3.htm

That way you can have any infinitely variable value, just not in one sweep.

 

[John Larkin]

On Sat, 18 Oct 2008 16:26:48 +0100, "ian field"
<gangprobing.alien@ntlworld.com> wrote:

.............and others for AGC use.

The result of numerous google searches has turned up conflicting answers,
I'm trying to find out how the discrete transistor AGC stages work in TV &
radio IF strips.

One answer states that varying the base voltage of the controlled stage
varies its input impedance to the previous stage by varying the B/E bias,
the other states that using variable bias varies the collector current - on
which the stage's gain is dependent.

As hardly any manufacturers still use discrete devices for this purpose
there seems to be very little I can find on this subject, please can anyone
help?

TIA.

Tube radios backed off the DC grid bias of several stages, uisng a
feedback signal from the detector. Negative on the grids reduces
transconductance hence gain.

Transistor radios worked the same way... reducing DC base voltage
reduces collector current and reduces transconductance hence gain.

The first of the cited "answers" is wrong... reducing base voltage
reduces transconductance and gain of this stage, but also reduces base
input impedance, which *increases* the gain of the previous stage
somewhat.

John

 

[sycochkn]

"michael nikolaou" <michaelnikolaou_remove_me_@yahoo.com> wrote in message
news:fq0kg4$1n3d$1@ulysses.noc.ntua.gr...

Hi

I have a 12 v relay driving an large 220 volt AC relay . Across the
contact of the driver relay i placed one RC snubber circut (27NF with 100
R resisitor in series) to help with some spikes that were influencing the
low voltage driver circuits.
The driver circuit is able to detect mains zero crossing and fire the
driver relay at an angle i choose .
From what i read the best point to switch off the power relay is at zero
crossing . I did that and i show a large spike up to 1 KV at the relay
contact followed by a decaying 500hz waveform to 0 volts . After some
experimentation the best point came exactly when switching off at the peak
of the mains voltage .At this point there is smooth decaying waveform to
0 volt after 5 periods of 500 HZ but no overshoot. The relay presents
no arcing. If i remove the snubber and make the experiment the best place
to switch is zero crossing but i also see large SHARP spikes up to 500
Volts Peak.
My question is
The switching with snubber must be made at zero crossing or at the peak of
an ac voltage waveform ?
What is the behaviour of the circuit ?.
As i understand any large spikes can harm the X2 capacitor i'm using so
what is the best operating practise ?.

Any help will be appreciated

Michael

Use a solid state releay and dont worry about it.

Bob

 

[gwatts]

Mad Scientist Jr wrote:

Does anyone know where you can order a plastic 9v battery holder with
a snap off cover that flush mounts in a project box, guitar body, etc?
It would be like the AA battery holder in this Synsonics Terminator
guitar except for 9v...

There are a few here:

http://www.guitarpartsresource.com/electrical_other.htm

 

( Www.g/lobwholesale.com )

Discount Coach Sandals, Dior Sandals, Prada Sandals, Chanel Sandals,
Versace Sandals, Crocs Sandals, LV Sandals, ( G U C C I ) Sandals, UGG
Sandals, Burberry Sandals, Women's Sandals Men's Slippers From
China

Brand Sunglasses Wholesale:

Discount, Prada Sunglasses
Discount, D&G Sunglasses
Discount, Fendi Sunglasses
Discount, Burberry Sunglasses
Discount, Chanel Sunglasses
Discount, LV Sunglasses
Discount, Dior Sunglasses
Discount, (G U C C I ) Sunglasses
Discount, Armani Sunglasses
Discount, Versace Sunglasses
Discount, A&F Sunglasses
Discount, LV Sunglasses

Wholesale, Prada Sunglasses
Wholesale, D&G Sunglasses
Wholesale, Fendi Sunglasses
Wholesale, Burberry Sunglasses
Wholesale, Chanel Sunglasses
Wholesale, LV Sunglasses
Wholesale, Dior Sunglasses
Wholesale, ( G U C C I ) Sunglasses
Wholesale, Armani Sunglasses
Wholesale, Versace Sunglasses
Wholesale, A&F Sunglasses
Wholesale, LV Sunglasses

 

hi
We are supplier in china Footwear Apparel Handbags Jeans&Pants Cap
Accessory(world famous brand)
1) Top quality, reasonable price, safe shipping, and best service
2) Sport shoes for men, women and kids with all sizes available
3) Sport shoes with different colors and styles available in stock
4) The material and size can be required to make in accordance with
customers' requests

Price :8-35usd 6-30EURO 5-30Pounds

size chart
Men Size:
US: 7 8 8.5 9 9.5 10 10.5 11 11.5 12 13 14 15
UK: 6 7 7.5 8 8.5 9 9.5 10 10.5 11 12 13 14
EUR: 40 41 42 42.5 43 44 44.5 45 45.5 46 47.5 48 49
Women Size:
US: 5 5.5 6 6.5 7 7.5 8 8.5
UK: 2.5 3 3.5 4 4.5 5 5.5 6
EUR: 35.5 36 36.5 37.5 38 38.5 39 40

Kid's
US: 11C 12C 12.5C 13C 1Y 1.5Y 2.5Y 3Y
EUR:28 29 30 31 32 33 34 35

Clothing Size:
S M L XL XXL XXXL XXXXL XXXXXL

Footwear
http://www.ciciaaa.cn
Apparel
http://www.ciciaaa.cn
Handbags
http://www.ciciaaa.cn
Jeans&Pants
http://www.ciciaaa.cn
Cap
http://www.ciciaaa.cn
Accessory
http://www.ciciaaa.cn
electronics
http://picasaweb.google.com/cicitrade.eleltronics
CiCi
www.ciciaaa.cn
MSN:cicitrade@live.cn
Building Material Market, Goutou Denizen Committee, XiaChen Office
Putian City Chengxiang District CiCi Trade Co., Ltd

 

[Salmon Egg]

In article <Xns9B7F7D737E7A61E7A@69.16.176.253>,
Sue Black <suebblack@com.invalid> wrote:

Can you help. I am new to this stuff.

The catalyst on my gas soldering iron doesn't glow as red as it used
to. Maybe some bits of material I used to file the iron's tip got
into the catalyst.

This is the first time I have heard of this kind of soldering iron, What

can you tell me about how it is constructed and used.

That said, I would guess that you removed a layerf of catalyst with any
filing of the tip.

Bill

--
Private Profit; Public Poop! Avoid collateral windfall!

 

[Franc Zabkar]

On Wed, 24 Dec 2008 11:24:35 -0800 (PST), Gene Stonerly
<stolen_energy@yahoo.com> put finger to keyboard and composed:

I want to build my own time machine.But for that purpose, I need a
flux capacitor.

Where can I buy a flux capacitor???

Why buy a flux capacitor when you can make your own:
http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=6084285

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[JeffM]

JeffM wrote:

Are you reporting the spam directly to Google?

clifto wrote:
Google does nothing.

Not *completely* true.
While Google Groups is *mostly* irresponsible WRT spam,
if they receive a *critical mass* of complaints (a very high
threshold)
they will terminate an account.

This is mostly useless, however,
as they don't cancel ALL accounts associated with that email address
and that person can still use any of those existing accounts
as well as using the EXACT SAME email address to open new accounts.

"Don't be evil". Hrrrmppf. Be clueless instead.

If they would extend their core business model (Filtering Data)
to Google Groups, they could weed out known spam.

This corporation is doing the bare minimum--and as I already said,
corporations don't change until something affects their bottom line.

 

[Franc Zabkar]

On Wed, 08 Aug 2007 18:01:51 -0700, PhattyMo <PhattyMo@nospam.gmail>
put finger to keyboard and composed:

Just digging through my junk box,I found a AN7221 AM tuner? IC.. I
can't seem to find any data on it though,Does anyone have the specs?

Thanks! Patrick

My vrt databook describes the AN7221 (18 MDIP) as a miniaturised
version of the AN7220 (18 DIP).

http://www.datasheets.org.uk/datasheet.php?article=804602
http://www.alldatasheet.com/datasheet-pdf/pdf/87437/PANASONIC/AN7220.html

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[RF King]

AAA RF Products Latest Catalog is now available.

Please Provide your mailing address to receive your copy at no charge.

Hope you guys all have a great day and I will look forward to helping
you on all your RF needs


Travis Currier
AAA RF Products
Phone: 949-481-3154
Email:sales@aaarfproducts.com
Website: www.aaarfproducts.com
Location: San Clemente, CA

 

[www.globwholesale.com]

Discount, LRG jeans, Evisu jeans, ED hardy jeans, COOGI jeans, Gino
Green Global jeans, Lacoste jeans, G-star jeans, Ked Robot jeans, Red
Monkey jeans, BBC jeans, Smet jeans, Seven jeans, Trun North Face
jeans, The Croun Holder jeans, Antik jeans, China Supply.

Supply BOSS t-shirts, men's Lacoste T-shirts, G U C C I women's t-
shirts,Polo T- shirts, BBC T-shirts, Bape T-shirts, ED hardy T-shirts,
Coogi T-shirts, Christian Audigier T-shirts, Gino Green Glalal (ggg) T-
shirts, Artful Dodger T-shirts, LRG T-shirts, Burberry T-shirts,
Affliction T-shirts....

( www.g lobwholesale.com )

 

[ehsjr]

hihihi wrote:

Lostgallifreyan wrote:


I just didn't want to recommend salt as it's very corrosive if any
gets onto metal.


My thoughts exactly

The sun has not shown itself for days, and is not expected to the coming
days.

I am now looking for a suitable secondhand mini oven at ebay and such
places.

I see microwave ovens thrown out often. Get one free,
put a bulb inside of it and let the bulb supply the heat.
You could even use a dimmer on the bulb and put a small
oven thermomenter inside to control the max. temperature.

Ed

 

[Michael A. Terrell]

Don McKenzie wrote:

I gave service to my country 50 years ago, but I don't see the need to
announce it to the rest of the world in every email.

I guess I am missing your point.

Its there to remind an online stalker that I'm still alive and
kicking.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Peter]

On Sep 15, 8:58 am, "robb" <s...@where.on.net> wrote:

hello,
I am trying to find a compatible replacement for an obsolete hard to find
part SN75518N

Afer much searching and reading and learning i thought maybe i could build a
compatible circuit to perform same function as SN75518 ? I think i can
cascade 2 of the MAX6971 to cover what is used on the 75518.

could someone look at these and see if i am on track or lost ?

if lost... can someone give me a landmark ?

use 2 of thesehttp://datasheets.maxim-ic.com/en/ds/MAX6971.pdf

to build this (-2 od the outputs)http://focus.ti.com/lit/ds/symlink/sn75518.pdf

to drive a 16 alpha-numeric char VFD (16 segment)

thanks for your time and help,
rob
Hi Rob,

why give up SN75518N? what is the quantity you need for your project?
if it is below 30k, you can continune to use it. we can support you at
this item.

best regards,
Peter
peter@expertonic.com
www.expertonic.com

 

[tony sayer]

In article <4963B300.C2EC6BAC@hotmail.com>, Eeyore <rabbitsfriendsandrel
ations@hotmail.com> scribeth thus

John Livingston wrote:

Floyd L. Davidson wrote:

You mean ITU-T standards, which is what both the UK and
Australia use. (It hasn't been CCITT for a long time.)

You are citing the bandwidth for an individual *channel*.
It is not possible to provide that sort of bandwidth on
every local loop, and therefore significantly less is
required for a complete connection or for any individual
loop.

Are we discussing the same thing, I wonder ? The "Local Loop" is the
exchange - subscriber path, and is not bandwidth limited other than by
the basic line parameters. Hence the reason a local loop can (typically)
support 8Mbit ADSL.

Or up to 24 Mbps ADSL2+ !

Graham

When you live -in- an exchange that is;!...
--
Tony Sayer

 

[Selkirk]

or if no cross, what is it?
Thanks.

 

[Owain]

Stevie Boy wrote:

While I'm not to sure what your hoping to achieve but you can buy a priority
(can be called by another name) switch which basically is a 2 outlet
telephone adaptor plug for less than a fiver that isolates the other
connected line when in use. This is achieved from a array of transistors
inside the unit which consumes it's power from the line.
This may be what your looking for.

Privacy adapter.

Quite a lot of them come with LEDs showing the line is in use. An LED is
one half of an optoisolator.

Owain

 

[Phil Allison]

"Don Pearce Fuckwit Pommy Cunt "

Very revealing table here, though.

http://en.wikipedia.org/wiki/Compact_fluorescent_lamp

120V incandescents are much better than 240V incandescents.

** That table says no such thing - fool.


You must be looking at a different table.


** Nope.

The one I'm looking at has,
for example, a 100W 240 volt lamp giving 1330lm, while a 100W 120V
lamp gives 1710lm.


** See the average lamp hours figure has dropped by 25% ???

750 to 1000 hours is pretty normal for the lifetime of a 240V bulb, so
no, there isn't a lifetime penalty.

** Looks like a nasty 25 % one to any sane person - CUNTHEAD !!

And the difference is there for every power all the
way down the table.


** So is the reduced life rating.

The data is taken off the marketing blurbs on maker's web sites, so is
basically bollocks and non comparable .

You got something better?

** YOU are the one that needs BETTER - ARSEHOLE .

A whole lot better than some bollocks on wiki.

Maybe try a nice net blog ??

If you ever get out of those *bogs* you like tolling.



....... Phil

 

[Chris Hills]

In article <7m9fa311isuk81tccs7icsea8091al8lo1@4ax.com>, Peter A Forbes
<diesel@easynet.co.uk> writes

Don't forget also that most people coming online in the past few years never
went through the BBS / Usenet phase that most older online people did, so they
had nothing to reference against.

You are wrong. We are STILL in the Usenet phase...

The problem is that a little knowledge is only a problem if you don't
know it is a little knowledge.

Some of the posters jump in with very little knowledge about the
Internet and completely the wrong attitude and then won't take advice.


--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
/\/\/ chris@phaedsys.org www.phaedsys.org \/\/\
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/