Op amps problem Gain Calculation

Brian Lund · Jul 11, 2005

there is no 7809

"there is no spoon" - sorry i had to do the matrix

your choice is 7805, 7808, 7812

The datasheet from SGS Thomson says that they produce the 78 series
regulator in the following voltages;
5, 5.2, 6, 8, 8.5, 9, 12, 15, 18 and 24V

Furthermore i have been working with the 7809 and others that you didn't
mention so i am sure they exist... Try google next time!

Brian Lund

Glen · Jul 11, 2005

On Mon, 11 Aug 2003 13:05:49 GMT, "Brett" <baisley@hotmail.com> wrote:

Some info on the switch would be helpful. The red lead could be
anything from an illumination lamp input, to a secondary output pole
on a dual-pole single-throw switch.

In 120V residential wiring, black is 120V, white is neutral, green or
bare copper is ground.

Hello

I recently moved into a new house and the jacuzzi there had a broken switch.
The previous owner took the old one in to the company and got a replacement,
however the style has changed.

In the "black box", there are 6 connectors. One side has 3 connectors
(white, black, green) that comes from the wall, and on the other side of the
box are 3 more connectors (green, white, black) that go to the pump.

The new switch has 4 wires coming from it, black, white, red, green. I
assume that if I put the black from the switch to the black coming from the
wall, the white from the switch to the white going to the pump, the red from
the switch to the black going to the pump, and the green to the green coming
from the wall, that should work, right?

Any help would be great. Thanks!

Brett

Richard Harvie · Jul 11, 2005

You can get 5000mcd whites in the UK for 25p a piece + Ł1 shipping per
order..

Care to tell us where from?

Brian Lund · Jul 11, 2005

You can get 5000mcd whites in the UK for 25p a piece + Ł1 shipping per
order..

Care to tell us where from?

Yeah, at these prices it even pays off to import

Brian

Dan Barlow · Jul 11, 2005

JD wrote:

Hi All,
Is it possible to dim the light output from very bright LED's??

Sure!

If you want to set a certain brightness level and keep it there,
you just change the resistor. Smaller resistance gives brighter
output, but you want to stay below the safe current for the LED.
Usually this is 20 mA but some of the Luxeon Emitters go up to
1/3 amp or more! Even Radio Shack still carries a few different
resistors. You'll want to look at the color code of the one
already in place and try doubling it to get half the brightness.

If you want to be able to adjust it, a good circuit can be made
to provide an "adjustable current regulator".
http://www.hw.cz/data_ic/lm317.pdf has an application note with
the full circuit. Almost any three pin voltage regulator can be
"adjusted" in this way. They are widely available and usually
not too expensive. You want a current range of 0 to 20mA or
whatever your LED lists as its maximum.

Finally, you can use a 555 timer to make it blink very fast.
Adjusting the "duty cycle" (the amount of time the LED is ON
during the cycle) will affect the apparent brightness. It
has the advantage of being a very linear adjustment.
-Dan Barlow

default · Jul 11, 2005

On Tue, 19 Aug 2003 21:38:02 GMT, JD <mill.tek@verizon.net> wrote:

Hi All,
Is it possible to dim the light output from very bright LED's??

Thanks,
Jim
Increase the value of the current limiting resistor to the LED. LED

brightness is determined by current flow.

Voltage across the LED stays relatively constant, for different
currents.

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
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Norman · Jul 11, 2005

Put less volts into them.

"JD" <mill.tek@verizon.net> wrote in message
news:_Mw0b.13011$_P1.5387@nwrddc01.gnilink.net...

Hi All,
Is it possible to dim the light output from very bright LED's??

Thanks,
Jim

JD · Jul 11, 2005

Dan Barlow wrote:

JD wrote:

Hi All,
Is it possible to dim the light output from very bright LED's??

Sure!

If you want to set a certain brightness level and keep it there,
you just change the resistor. Smaller resistance gives brighter
output, but you want to stay below the safe current for the LED.
Usually this is 20 mA but some of the Luxeon Emitters go up to
1/3 amp or more! Even Radio Shack still carries a few different
resistors. You'll want to look at the color code of the one
already in place and try doubling it to get half the brightness.

If you want to be able to adjust it, a good circuit can be made
to provide an "adjustable current regulator".
http://www.hw.cz/data_ic/lm317.pdf has an application note with
the full circuit. Almost any three pin voltage regulator can be
"adjusted" in this way. They are widely available and usually
not too expensive. You want a current range of 0 to 20mA or
whatever your LED lists as its maximum.

Finally, you can use a 555 timer to make it blink very fast.
Adjusting the "duty cycle" (the amount of time the LED is ON
during the cycle) will affect the apparent brightness. It
has the advantage of being a very linear adjustment.
-Dan Barlow

Dan,

Thanks. I do specifically want to be able to control the brightness (as
one does with incandescent and rheostat).

Jim

miketinte · Jul 11, 2005

Actually, it's the CURRENT through an LED that controls its brightness.

"Norman" <stayforthedayandgo@yahoo.com> wrote in message news:<bhu6sc$niv$1@titan.btinternet.com>...

Put less volts into them.

"JD" <mill.tek@verizon.net> wrote in message
news:_Mw0b.13011$_P1.5387@nwrddc01.gnilink.net...
Hi All,
Is it possible to dim the light output from very bright LED's??

Thanks,
Jim

@ spam]grnetx.com · Jul 11, 2005

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

The LM317, not a very good choice;

Not Low Dropout, requires a three volt difference in i/o voltages,
however it does handle around 1.5A. Try this part #: KA278R09TU, it can
be ordered from Fairchild Semi or any one of their agents, and the good
news, is they offer free samples of it, so you can probably hook
yourself up with 5 -> 10 for free

. Dropout is rated at "below 0.5V"
and can handle around 2A -- This regulator has various functions such as
peak current protection, thermal shut down, overvoltage protection and
output disable function.

Datasheet: http://www.fairchildsemi.com/ds/KA/KA278R09.pdf
Product Page: http://www.fairchildsemi.com/pf/KA/KA278R09.html

wpa wrote:

| use LM317 with 2 resistors calculated for 9V.
|
| "Lawrence Lucier" <llucier@shaw.ca> schreef in bericht
| news:3F331787.8BA20910@shaw.ca...
|
|>Howdy all.....

|
|
|

- --

Regards,

Sean Coyle
President
Greenroom Networx
Ph: 604.941.7832
Fx: 604.941.7803

"Working to create teleports for economic and business development,
Intelligent City, information and communications technology"
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Version: GnuPG v1.2.2 (MingW32)

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Jack · Jul 11, 2005

Hi Edward,
Do a "Google" search you will get hunderds of hits.
Jack
"Edward Cit" <ed@stevens8436.fslife.co.uk> wrote in message
news:bi58kh$mt8$1@newsg1.svr.pol.co.uk...

Hi,

I need to interface a PC's floppy disk drive to a microprocessor based
system. Does anyone know what the interface to a floppy disk drive is
called? Also, does anyone know what the specification is called?

Thanks in advance,

Alistair · Jul 11, 2005

Sorry, after posting, I realised I had spelt Meccano wrong, its not
Mechano.....duh

Cheers

Alistair

"Alistair" <alistair.echlin@btinternet.com> wrote in message
news:bi77us$m21$1@titan.btinternet.com...

Hi there, I came across a site months ago, and I am having real trouble
finding it again!!!!

Its called (or was) Electronics in Mechano www.elecinmech.com

Has it changed name, been taken off net or what?

Hope someone can help me

Thank you

Alistair

Jason · Jul 11, 2005

I see all these posts wanting to go from 12v to 9vdv

I would just use 2 resistors to split the potential difference? What am I
missing why are "LM317" etc a better chocice?

"@ spam]grnetx.com" <""sean.coyle[no \"@ spam]grnetx.com"> wrote in message
news:2Qb1b.801082$3C2.18117583@news3.calgary.shaw.ca...

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

The LM317, not a very good choice;

Not Low Dropout, requires a three volt difference in i/o voltages,
however it does handle around 1.5A. Try this part #: KA278R09TU, it can
be ordered from Fairchild Semi or any one of their agents, and the good
news, is they offer free samples of it, so you can probably hook
yourself up with 5 -> 10 for free . Dropout is rated at "below 0.5V"
and can handle around 2A -- This regulator has various functions such as
peak current protection, thermal shut down, overvoltage protection and
output disable function.

Datasheet: http://www.fairchildsemi.com/ds/KA/KA278R09.pdf
Product Page: http://www.fairchildsemi.com/pf/KA/KA278R09.html

tim kettring · Jul 11, 2005

Jason ,

Firstly , 2 resistors are a waste of watts , secondly any appreciable
current draw at the split will change the voltage at the split .

If I want 9v from 12v , I just use one of my 100 5v regs i got free
off parts boards---I put some cheap generic diodes in the reference
leg of the reg ( they are 7805s good for at least 1 amp .

Am LM317 to me is only worth the bother and cost$ for Variable Voltage
output power supplies . I think its only good for about 1 or so amp
anyway , if I need more current I use a power junction transistor PNP
, NPN whatever works .

tim CET MD-238

"Jason" <jason@spam.net> wrote in message news:<0YJ1b.2421$ED7.20707394@news-text.cableinet.net>...

I see all these posts wanting to go from 12v to 9vdv

I would just use 2 resistors to split the potential difference? What am I
missing why are "LM317" etc a better chocice?

"@ spam]grnetx.com" <""sean.coyle[no \"@ spam]grnetx.com"> wrote in message
news:2Qb1b.801082$3C2.18117583@news3.calgary.shaw.ca...
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

The LM317, not a very good choice;

Not Low Dropout, requires a three volt difference in i/o voltages,
however it does handle around 1.5A. Try this part #: KA278R09TU, it can
be ordered from Fairchild Semi or any one of their agents, and the good
news, is they offer free samples of it, so you can probably hook
yourself up with 5 -> 10 for free . Dropout is rated at "below 0.5V"
and can handle around 2A -- This regulator has various functions such as
peak current protection, thermal shut down, overvoltage protection and
output disable function.

Datasheet: http://www.fairchildsemi.com/ds/KA/KA278R09.pdf
Product Page: http://www.fairchildsemi.com/pf/KA/KA278R09.html

tim kettring · Jul 11, 2005

Yes, 7809s are the easiest , but not cheap$ or easily buyable...except
MABE the high$ shack . Definately use a heat sink it approaches hot to
touch when running under full load !!! ( whatever reg or xsistor you
use )

tim

"Brian Lund" <vult2@hotmail.com> wrote in message news:<3f3398b3$0$76154$edfadb0f@dread11.news.tele.dk>...

Use a 7809 Voltage regulator

Maybe a little heatsink should be used also, there will be generated 3W of
heat

Brian

tim kettring · Jul 11, 2005

Jimmy ,

I hope you arent bothering with nixies on a new project, they are antiques .

try

http://www.tubesandmore.com/

when their database comes up again .
( keywords: electronic tubes )

Good Luck , you will need it .

tim CET

"Jimmy" <Gfender@carolina.rr.com> wrote in message news:<Vf_0b.5867$J16.344738@twister.southeast.rr.com>...
> Need 7441 nixie drivers will trade for NOS tubes or buy.

Edward Cit · Jul 11, 2005

"Edward Cit" <ed@stevens8436.fslife.co.uk> wrote in message
news:bi58kh$mt8$1@newsg1.svr.pol.co.uk...

Hi,

I need to interface a PC's floppy disk drive to a microprocessor based
system. Does anyone know what the interface to a floppy disk drive is
called? Also, does anyone know what the specification is called?

Thanks in advance,

Thanks for you replies.

I've looked on the recommended site and I've also done a thousand searches
in Google, but im still unable to find a official specification. I've got
the pin out of the connector but I need know what the signals mean etc etc.

Does anyone know the name or the location of the specification?

Thanks,

JD · Jul 11, 2005

Terry Given wrote:

Hi All,
Is it possible to dim the light output from very bright LED's??

Sure!

If you want to set a certain brightness level and keep it there,
you just change the resistor. Smaller resistance gives brighter
output, but you want to stay below the safe current for the LED.
Usually this is 20 mA but some of the Luxeon Emitters go up to
1/3 amp or more! Even Radio Shack still carries a few different
resistors. You'll want to look at the color code of the one
already in place and try doubling it to get half the brightness.

If you want to be able to adjust it, a good circuit can be made
to provide an "adjustable current regulator".
http://www.hw.cz/data_ic/lm317.pdf has an application note with
the full circuit. Almost any three pin voltage regulator can be
"adjusted" in this way. They are widely available and usually
not too expensive. You want a current range of 0 to 20mA or
whatever your LED lists as its maximum.

Finally, you can use a 555 timer to make it blink very fast.
Adjusting the "duty cycle" (the amount of time the LED is ON
during the cycle) will affect the apparent brightness. It
has the advantage of being a very linear adjustment.
-Dan Barlow

Dan,
Thanks. I do specifically want to be able to control the brightness (as
one does with incandescent and rheostat).

Jim

One other point about Pulse-Width-Modulation (PWM) - it does not change the
chromaticity (colour) of the LED. Changing the current does. If you wanna
build a giant LED tv screen, PWM is the only way of doing it, else the
colours vary with brightness. If on the other hand you dont care, a pot in
series with a small resistor (sets max. current) is the easiest way by far.
play with log & linear taper, my guess is log would work best (based on no
thought whatsoever).

Thanks All.

Jim

Terry Given · Jul 11, 2005

Hi All,
Is it possible to dim the light output from very bright LED's??

Sure!

If you want to set a certain brightness level and keep it there,
you just change the resistor. Smaller resistance gives brighter
output, but you want to stay below the safe current for the LED.
Usually this is 20 mA but some of the Luxeon Emitters go up to
1/3 amp or more! Even Radio Shack still carries a few different
resistors. You'll want to look at the color code of the one
already in place and try doubling it to get half the brightness.

If you want to be able to adjust it, a good circuit can be made
to provide an "adjustable current regulator".
http://www.hw.cz/data_ic/lm317.pdf has an application note with
the full circuit. Almost any three pin voltage regulator can be
"adjusted" in this way. They are widely available and usually
not too expensive. You want a current range of 0 to 20mA or
whatever your LED lists as its maximum.

Finally, you can use a 555 timer to make it blink very fast.
Adjusting the "duty cycle" (the amount of time the LED is ON
during the cycle) will affect the apparent brightness. It
has the advantage of being a very linear adjustment.
-Dan Barlow

Dan,
Thanks. I do specifically want to be able to control the brightness (as
one does with incandescent and rheostat).

Jim

One other point about Pulse-Width-Modulation (PWM) - it does not change the
chromaticity (colour) of the LED. Changing the current does. If you wanna
build a giant LED tv screen, PWM is the only way of doing it, else the
colours vary with brightness. If on the other hand you dont care, a pot in
series with a small resistor (sets max. current) is the easiest way by far.
play with log & linear taper, my guess is log would work best (based on no
thought whatsoever).

Wouter van Ooijen (www.vo · Jul 11, 2005

I thought it would be fun to have an alphanumeric display on my computer to
show things like the current mp3 playing. I found a few displays but they
needed a parallel connection but I think I need a serial connection because
I only have USB available. Unfortunately the serial alphanumeric displays
were alot more expensive and also required 5 connections (perhaps from a
RS-232 kinda thing). I also looked for a usb to serial IC but they seemed
really expensive ($70).

I sell an USB-to-serial IC (FT232BM), but that chip has *very* tiny
legs, so I would not advise a beginner to try to solder it.

And you would still need a serial-to-LCD chip.

But maybe you can use a serial-interface LCD with a common
USB-to-serial converter (I sell both!)

If you have some patience: I am working on an USB interface for
standard LCDs.

Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting

Op amps problem Gain Calculation

Brian Lund

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Glen

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Richard Harvie

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Brian Lund

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Dan Barlow

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default

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Norman

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JD

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miketinte

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@ spam]grnetx.com

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Jack

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Alistair

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Jason

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tim kettring

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