Op amps problem Gain Calculation

[John G]

Steve Gonedes explained on 1/06/2013 :

Bob Monsen <rcsurname@comcast.net> writes:

On Sun, 19 Feb 2006 13:59:34 +0000, nibbles wrote:

Hi all,

I'm trying to create an LED lighting system for my staircase - which will
have a row of 15 LEDs under each tread bullnose, that are switched on/off
by pressure mats located at both top and bottom of the staircase.
I intend to wire up the LEDs as 65 parallel arrays of 3 LEDs operating on
12v @15ma/3.5v using a 100 ohm resistor for each (195 in total so lots of
soldering to be done!).
The above was calculated using the this online calculator
http://led.linear1.org/led.wiz so if my description isn't clear, pop them
details into the calc' for a diagram.

What I need help with is a simple(ish) diagram to operate the toggle
function as mentioned above, eg; Switch on when someone steps on the bottom
pad and off when they step on the top pad - or vice-versa.

Any suggestions would be greatly appreciated.

Do you have the pressure mats already? If not, a cheaper alternative might
be a sharp IR sensor, like a GP2D12. Mount it facing across the step,
and you'll be able to get a voltage pulse when somebody steps on the stair.

Arg! The sharp IR sensor....

That post is 7 years old now so he has fallen down the dark stairs.
:-(
Anyway he wanted a toggle circuit to switch either way with the press
of the top or bottom switches not a simple toogle switch. :-Z

--
John G

 

[Jasen Betts]

On 2013-06-01, John G <greentest@ozemail.com.au> wrote:

Steve Gonedes explained on 1/06/2013 :
Bob Monsen <rcsurname@comcast.net> writes:

On Sun, 19 Feb 2006 13:59:34 +0000, nibbles wrote:

Hi all,

I'm trying to create an LED lighting system for my staircase - which will
have a row of 15 LEDs under each tread bullnose, that are switched on/off
by pressure mats located at both top and bottom of the staircase.
I intend to wire up the LEDs as 65 parallel arrays of 3 LEDs operating on
12v @15ma/3.5v using a 100 ohm resistor for each (195 in total so lots of
soldering to be done!).
The above was calculated using the this online calculator
http://led.linear1.org/led.wiz so if my description isn't clear, pop them
details into the calc' for a diagram.

What I need help with is a simple(ish) diagram to operate the toggle
function as mentioned above, eg; Switch on when someone steps on the bottom
pad and off when they step on the top pad - or vice-versa.

Any suggestions would be greatly appreciated.

Do you have the pressure mats already? If not, a cheaper alternative might
be a sharp IR sensor, like a GP2D12. Mount it facing across the step,
and you'll be able to get a voltage pulse when somebody steps on the stair.

Arg! The sharp IR sensor....

That post is 7 years old now so he has fallen down the dark stairs.
:-(
Anyway he wanted a toggle circuit to switch either way with the press
of the top or bottom switches not a simple toogle switch. :-Z

SPDT is a fairly simple switch, a bedlamp switch won't do it,
but many others will.

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

Or try http://www.youpcb.com

5cm x 5cm 10 PCS for $29 shipped, 10cm x10 cm 10 PCS for $44 shipped


On Tuesday, March 11, 2003 8:52:17 AM UTC-4, P wrote:

"SpeedDemon2198" <speeddemon2198@wideopenwest.com> wrote in
news:efacnRwoYdnGg_ajXTWcow@wideopenwest.com:

You don't actually *need* a UV lightbox. Pick up a florescent fixture and a
full spectrum bulb. I use it for exposing UV sensitized boards all the
time. You'll have to experiment some to find the correct exposure time
(though thats true even if using a UV box).

Even regular florescent bulbs (CW or WW) work, they just need that much
longer for exposures.

Hi,

I've produced PCBs by designing them using PC tools then passing the
artwork
onto others for them to produce the actual boards. However I'd like
to be able to do it myself.

A UV lightbox is far too expensive and is (as far as I know) the only
way
to
produce PCBs from a PC. I've seen "iron on" things that you print
onto using a laser but these seem quite expensive for a one time,
throw away
use.

 

[Uncle Peter]

Oops! Why would a surface mount ferrite bead catch fire dramatically? There was as much smoke as lighting a cheap match.

http://petersphotos.com/temp/Dead%20miner.jpg

--
Confucius say lion with small penis must compensate with mighty roar.

 

[Rheilly Phoull]

On 15/08/14 22:48, Uncle Peter wrote:

Oops! Why would a surface mount ferrite bead catch fire dramatically?
There was as much smoke as lighting a cheap match.

http://petersphotos.com/temp/Dead%20miner.jpg

Short in the winding?

 

[Uncle Peter]

On Sat, 16 Aug 2014 06:36:22 +0100, Rheilly Phoull <rheilly@bigslong.com> wrote:

On 15/08/14 22:48, Uncle Peter wrote:
Oops! Why would a surface mount ferrite bead catch fire dramatically?
There was as much smoke as lighting a cheap match.

http://petersphotos.com/temp/Dead%20miner.jpg

Short in the winding?

AFAIK these things are placed in series with the device? So a short would simply be as though they didn't exist.

--
"So it was the first fuckin' leave in six fuckin' months. I dropped off my fuckin' uniform at the fuckin' Y, went to a fuckin' bar, and picked up a fuckin' broad. I took her to a fuckin' hotel, laid her out on the fuckin' bed, and had sexual intercourse."

 

[Ian Field]

"Uncle Peter" <no@spam.com> wrote in message
newsp.xks9r9ivswtmtb@red.lan...

On Sat, 16 Aug 2014 06:36:22 +0100, Rheilly Phoull <rheilly@bigslong.com
wrote:

On 15/08/14 22:48, Uncle Peter wrote:
Oops! Why would a surface mount ferrite bead catch fire dramatically?
There was as much smoke as lighting a cheap match.

http://petersphotos.com/temp/Dead%20miner.jpg

Short in the winding?

AFAIK these things are placed in series with the device? So a short would
simply be as though they didn't exist.

Whatever it was - you broke it.

 

[Uncle Peter]

On Sun, 24 Aug 2014 20:17:17 +0100, Ian Field <gangprobing.alien@ntlworld.com> wrote:

"Uncle Peter" <no@spam.com> wrote in message
newsp.xks9r9ivswtmtb@red.lan...
On Sat, 16 Aug 2014 06:36:22 +0100, Rheilly Phoull <rheilly@bigslong.com
wrote:

On 15/08/14 22:48, Uncle Peter wrote:
Oops! Why would a surface mount ferrite bead catch fire dramatically?
There was as much smoke as lighting a cheap match.

http://petersphotos.com/temp/Dead%20miner.jpg

Short in the winding?

AFAIK these things are placed in series with the device? So a short would
simply be as though they didn't exist.

Whatever it was - you broke it.

It was my fault for shorting the fan output. But that was connected directly to the power input and nothing to do with the busted ferrite bead. Mind you a loose fan wire could have touched the bead....

--
California lawmakers are now proposing an amendment that would allow 14 year olds a quarter vote and 16 year olds a half a vote in all state elections.
How stupid is this? Don't they have enough trouble counting WHOLE votes? How are they going to figure out fractions?!

 

[Ian Field]

"Uncle Peter" <no@spam.com> wrote in message
newsp.xk32rqukswtmtb@red.lan...

On Sun, 24 Aug 2014 20:17:17 +0100, Ian Field
gangprobing.alien@ntlworld.com> wrote:



"Uncle Peter" <no@spam.com> wrote in message
newsp.xks9r9ivswtmtb@red.lan...
On Sat, 16 Aug 2014 06:36:22 +0100, Rheilly Phoull
rheilly@bigslong.com
wrote:

On 15/08/14 22:48, Uncle Peter wrote:
Oops! Why would a surface mount ferrite bead catch fire dramatically?
There was as much smoke as lighting a cheap match.

http://petersphotos.com/temp/Dead%20miner.jpg

Short in the winding?

AFAIK these things are placed in series with the device? So a short
would
simply be as though they didn't exist.

Whatever it was - you broke it.

It was my fault for shorting the fan output. But that was connected
directly to the power input and nothing to do with the busted ferrite
bead. Mind you a loose fan wire could have touched the bead....

Do you break *EVERYTHING* you get your hands on?!

 

[Uncle Peter]

On Sun, 24 Aug 2014 21:57:28 +0100, Ian Field <gangprobing.alien@ntlworld.com> wrote:

"Uncle Peter" <no@spam.com> wrote in message
newsp.xk32rqukswtmtb@red.lan...
On Sun, 24 Aug 2014 20:17:17 +0100, Ian Field
gangprobing.alien@ntlworld.com> wrote:



"Uncle Peter" <no@spam.com> wrote in message
newsp.xks9r9ivswtmtb@red.lan...
On Sat, 16 Aug 2014 06:36:22 +0100, Rheilly Phoull
rheilly@bigslong.com
wrote:

On 15/08/14 22:48, Uncle Peter wrote:

Short in the winding?

AFAIK these things are placed in series with the device? So a short
would
simply be as though they didn't exist.

Whatever it was - you broke it.

It was my fault for shorting the fan output. But that was connected
directly to the power input and nothing to do with the busted ferrite
bead. Mind you a loose fan wire could have touched the bead....

Do you break *EVERYTHING* you get your hands on?!

Yes, and sometimes it's on purpose.

--
I still say a church steeple with a lightning rod on top shows a lack of confidence.

 

[Ian Field]

"Uncle Peter" <no@spam.com> wrote in message
newsp.xk37lx2eswtmtb@red.lan...

On Sun, 24 Aug 2014 21:57:28 +0100, Ian Field
gangprobing.alien@ntlworld.com> wrote:



"Uncle Peter" <no@spam.com> wrote in message
newsp.xk32rqukswtmtb@red.lan...
On Sun, 24 Aug 2014 20:17:17 +0100, Ian Field
gangprobing.alien@ntlworld.com> wrote:



"Uncle Peter" <no@spam.com> wrote in message
newsp.xks9r9ivswtmtb@red.lan...
On Sat, 16 Aug 2014 06:36:22 +0100, Rheilly Phoull
rheilly@bigslong.com
wrote:

On 15/08/14 22:48, Uncle Peter wrote:

Short in the winding?

AFAIK these things are placed in series with the device? So a short
would
simply be as though they didn't exist.

Whatever it was - you broke it.

It was my fault for shorting the fan output. But that was connected
directly to the power input and nothing to do with the busted ferrite
bead. Mind you a loose fan wire could have touched the bead....

Do you break *EVERYTHING* you get your hands on?!

Yes, and sometimes it's on purpose.

DIY brain surgery kit is in the post.

 

[Tough Guy no. 1265]

On Sat, 21 Feb 2015 22:14:47 -0000, JNugent <jenningsltd@fastmail.fm> wrote:

On 21/02/2015 17:38, Tough Guy no. 1265 wrote:

This has been asked before, and I only got stupid answers like "the cars
need time to stop". Why is it when you press the button on a pelican
crossing (just a basic one, not at a junction), there is always a delay
of about 10 seconds before the lights for the cars change? And no it
isn't to allow the cars time to stop. It makes no difference if the
light sequence starts at or 10 seconds after the pedestrian pressing the
button. Just think about it.

Please sir!

I know the answer to this one!

The delay is built-in in order to damp the effect of several pedestrians
(or even one) pressing the buttons repeatedly in quick succession.

If the circuitry responded immediately (I know of no reason why that
couldn't physically be arranged), at a point where pedestrians crossing
the road arrived in a near-constant stream, and bear8ing in mind that
the lights must allow the individual a reasonable amount of time to
cross even if he is disabled or has restricted mobility, the lights for
traffic would be red for too much of the time and green for an
insufficient time. At very busy locations, the lights might be red for
traffic more or less constantly during the rush hour, which isn't a good
thing even for pedestrians, many of whom intend to travel (or have just
arrived) by road vehicle.

What an odd way to program it. Surely all it needs to do is to leave a gap AFTER the car lights go green again, before it can react again. Unless it has VERY simple circuitry, like it's made of 555 timers or something, this could be done just as easily.

alt.electronics added.

--
There once was a time when all people believed in god and the church ruled. This time was called the Dark Ages. -- Richard Lederer

 

[Mick]

"Tough Guy no. 1265" <no@spam.com> wrote in message
newsp.xufk1cotcpfvgl@red.lan...

On Sat, 21 Feb 2015 22:14:47 -0000, JNugent <jenningsltd@fastmail.fm
wrote:

On 21/02/2015 17:38, Tough Guy no. 1265 wrote:

This has been asked before, and I only got stupid answers like "the cars
need time to stop". Why is it when you press the button on a pelican
crossing (just a basic one, not at a junction), there is always a delay
of about 10 seconds before the lights for the cars change? And no it
isn't to allow the cars time to stop. It makes no difference if the
light sequence starts at or 10 seconds after the pedestrian pressing the
button. Just think about it.

you have fucked up the driving group and the cycling group with your
shit. now you are after fucking up this one with your shit.

phucker is a trolling prick, the unemployed, lazy, psychotic wanker should
be ignored.

 

[NEMO]

On 2/22/2015 11:21 AM, Mick wrote:

"Tough Guy no. 1265" <no@spam.com> wrote in message
newsp.xufk1cotcpfvgl@red.lan...
On Sat, 21 Feb 2015 22:14:47 -0000, JNugent <jenningsltd@fastmail.fm
wrote:

On 21/02/2015 17:38, Tough Guy no. 1265 wrote:

This has been asked before, and I only got stupid answers like "the cars
need time to stop". Why is it when you press the button on a pelican
crossing (just a basic one, not at a junction), there is always a delay
of about 10 seconds before the lights for the cars change? And no it
isn't to allow the cars time to stop. It makes no difference if the
light sequence starts at or 10 seconds after the pedestrian pressing the
button. Just think about it.

you have fucked up the driving group and the cycling group with your
shit. now you are after fucking up this one with your shit.

phucker is a trolling prick, the unemployed, lazy, psychotic wanker should
be ignored.

Absolutely!

 

[The Peeler]

On Sun, 22 Feb 2015 19:01:44 -0800, The Rectum, the resident psychopath of
sci and scj and Usenet's famous sexual cripple, FAKING his time zone again,
farted:

phucker is a trolling prick, the unemployed, lazy, psychotic wanker should
be ignored.

Absolutely!

HAH!!! You DID feel personally addressed again when "unemployed, lazy,
psychotic wanker" was mentioned, right, The Rectum? And RIGHTLY so! LOL

--
Silk from "uk.rec.driving" to our resident psycho:
"It's a shame there isn't a degree in wanking. They'd make YOU a professor."
MID: <1378226604380668849.677318me-privacy.net@news.aioe.org>

 

[James Wilkinson Sword]

On Fri, 24 Mar 2017 22:12:09 -0000, <fredal185263@gmail.com> wrote:

On Friday, March 24, 2017 at 5:02:50 PM UTC, James Wilkinson Sword wrote:
On Fri, 24 Mar 2017 16:33:59 -0000, GB <NOTsomeone@microsoft.com> wrote:

Once again you demonstrate that you haven't a clue about how to drive.
That near collision was 100% your fault, you idiot.

An indicator is required by law.

I thought you were opposed to laws?

Only the stupid ones.

> Libertarian- An anarchist who wants Police protection from his slaves.

Anything is more sensible in the correct dosage. Police should be stopping murderers, not people who download an mp3.

******************

I will say this one more time, stop fucking about with the newsgroup line.

 

[Mary-Jane Rottencrotch]

On 2007-01-19 12:13, Peter Fucker wrote:
> Is it really true that turning on a microwave with nothing in it will break it?

Derp.

 

[James Wilkinson Sword]

On Mon, 11 Dec 2017 04:07:43 -0000, Mary-Jane Rottencrotch <usenet@buttocks.local> wrote:

On 2007-01-19 12:13, Peter Fucker wrote:
Is it really true that turning on a microwave with nothing in it will break it?

Derp.

It was a sensible question. This could be done by accident.

--
If you had to identify, in one word, the reason why the human race has not achieved, and never will achieve, its full potential, that word would be "meetings."

 

[rickman]

James Wilkinson Sword wrote on 12/11/2017 11:50 AM:

On Mon, 11 Dec 2017 04:07:43 -0000, Mary-Jane Rottencrotch
usenet@buttocks.local> wrote:

On 2007-01-19 12:13, Peter Fucker wrote:
Is it really true that turning on a microwave with nothing in it will
break it?

Derp.

It was a sensible question. This could be done by accident.

I interviewed with a place once that was doing something with testing
microwave ovens. They ran them all the time with nothing in them. I had
always read that you should not operate them with nothing to absorb the
energy and mentioned that. I got a strange look from the guy. Obviously
the energy that would be absorbed is within the limits of what the ovens
were designed to get rid of.

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998

 

[James Wilkinson Sword]

On Tue, 12 Dec 2017 03:49:55 -0000, rickman <gnuarm@gmail.com> wrote:

James Wilkinson Sword wrote on 12/11/2017 11:50 AM:
On Mon, 11 Dec 2017 04:07:43 -0000, Mary-Jane Rottencrotch
usenet@buttocks.local> wrote:

On 2007-01-19 12:13, Peter Fucker wrote:
Is it really true that turning on a microwave with nothing in it will
break it?

Derp.

It was a sensible question. This could be done by accident.

I interviewed with a place once that was doing something with testing
microwave ovens. They ran them all the time with nothing in them. I had
always read that you should not operate them with nothing to absorb the
energy and mentioned that. I got a strange look from the guy. Obviously
the energy that would be absorbed is within the limits of what the ovens
were designed to get rid of.

You'd think there would be something that absorbs microwaves that miss the food. And you'd think such a thing would have a thermal cutout. Anybody want to try it?

--
"It was reported last week that a citizen's group is trying to remove porn channels from hotels across the country."
"The group is called the Coalition of People Who Want to Ruin Everything."