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Use a bi-color LED as an ammeter?

J

John Popelish

Jan 1, 1970
0
OK I've put up a crude drawing at
http://myweb.cableone.net/zirconx/LEDammeter.gif


LEDs are available that run off as little as 2ma of current.

Unfortunately for your circuit, they take several volts across them
before that 2 ma. will pass through them. If the battery cable drops
that much voltage, it will glow in the dark.
If I had two wires to run power from the battery to the bike, current
would run through both of them. This is essentially what I am doing
here, but one wire has much less resistance than the other and the
other has an LED in it. Could I get 2ma would flow through the other
wire?

Through a wire, yes. Through an LED in series with that wire, no.
 
R

Rheilly Phoull

Jan 1, 1970
0
Paul Hovnanian P.E. said:
Tim said:
Perhaps for _your_ motorcycle. The most common color deficiency
experienced by humans, which occurs most often in men and boys, is an
inability to distinguish green, red and gray.

So you can do this (after adding a suitable transresistance amplifier to
address the 1.6V threshold problem), but if you loan your motorcycle to
me I won't be able to tell charge from discharge.

After solving the amplifier problem, just add two extra green LEDs.
Configure the bi-color LED to produce a horizontal red or green bar and
the auxiliary green LEDs to add green squares above and below the bar.
Now you have a red '-' sign for discharge and a green '+' sign for
charge.

--
Paul Hovnanian mailto:p[email protected]
------------------------------------------------------------------
Disclaimer - These opiini^H^H damn! ^H^H ^Q ^[ .... :w :q :wq :wq! ^d
exit X Q ^C ^? :quitbye CtrlAltDel ~~q :~q logout save/quit :!QUIT
^[zz ^[ZZZZZZ ^H man vi ^@ ^L ^[c ^# ^E ^X ^I ^T ? help helpquit ^D
man quit ^C ^c ?Quit ?q CtrlShftDel "Hey, what does this button d..."

What you really need is an ammeter that under no current flow indicates '12
oclock' and for discharge the needle swings to the left, should the
conditions produce a charge to the battery the needle swings to the right. I
reckon this could really catch on if someone chooses to make such devices.
Even the colour blind could interpret that.
 
J

jtaylor

Jan 1, 1970
0
Tim Wescott said:
One of them -- and I think it was the green/blue deficiency -- was very
highly prized for infantrymen during WWII because they tended to see
camouflage easier. Ordinary folk would be so distracted by the color
match that they wouldn't notice the tones being slightly off, the folks
with this deficiency would then be able to see the mismatch in the pattern.

My flute teacher (when I was a kid) told me his job was to look at
reconnaisance photos duing the second war - don't remember which type of
colour-blindness he had but they got him to do that for the same reason.
 
R

Rich Grise

Jan 1, 1970
0
Green/blue problem is a very unusual defect. 15 ohms is much easier.
Crossed eyes. (;-)

Purple/brown can be difficult, especially under incandescent light. But
it doesn't normally cause problems with resistors, because 2.1 and 4.1
aren't preferred values. 75 ohms/15 ohms is a possible confusion.

Speaking of color balance - in 1963, the family got a convertible with a
red interior. Now that I think back, that was Dad's mid-life crisis car.
;-) I remember the first time we drove under mercury-vapor streetlights;
the red interior turned a very nice, conservative brown. ;-)

Cheers!
Rich
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Tim Wescott


Those are usually called '4-band'. Brown, black, brown, gold.


I think you mean 5-band. They confuse practically everyone. Brown,
brown, black, black, brown? Or is that brown, black, black, brown,
brown?

I thought that either they'd be bunched up to the left, or the tolerance
band has a wider gap.

Thanks,
Rich
 
R

Rich Grise

Jan 1, 1970
0
Just so I'm clear - You're being sarcastic, right?

Will you please copy/paste part of what you're responding to?

It's easy to know what the F*** you're talking about when you've got
the post rignt in front of you, typing into google's little input
box, but it sure makes for some lame posts when you're reading the NG
with a real newsreader.

And yes, Rheilly was being sarcastic (about the ammeter), but I'm not.

Thanks,
Rich
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
wrote (in said:
I thought that either they'd be bunched up to the left, or the tolerance
band has a wider gap.
Try that with one of those delightful through-hole parts that is all of
3 mm long.
 
Blame Google's new service. It's inconsistent and inconvenient.
Sometimes when you click reply, some kind of Javascript-induced text
box opens with nothing quoted in it (that's what I'm typing in now).
Sometimes, it opens the old-style full-page posting window with the
original message quoted and attributed.
 
R

Rich Grise

Jan 1, 1970
0
Blame Google's new service. It's inconsistent and inconvenient.
Sometimes when you click reply, some kind of Javascript-induced text
box opens with nothing quoted in it (that's what I'm typing in now).
Sometimes, it opens the old-style full-page posting window with the
original message quoted and attributed.

Yes. When this text box opens, that you typed this in, can you still read
the post to which you're responding?

If so, then drag the mouse over it
1. Move cursor to the left of the first line you want to copy.
2. Press and hold the mouse button.
3. Drag the cursor to the end of the text you want to copy. This will
higlight it.
4. Release the mouse button.
And copy it
5. Press Control-C - hold down the "control" key, and while it's down,
press and release the "C" key. Release the control key.

Then move the curser to the inside of your text box where you want the
quoted text to appear, and press Control-V. This pastes.

Good Luck!
Rich
 
Besides the fact that there are apparently only two people who care (or
two people who read my posts - take your pick, I'm not fussy) - you
missed the fact that this doesn't make it a quote.
 
C

Clarence_A

Jan 1, 1970
0
Besides the fact that there are apparently only two people who care (or
two people who read my posts - take your pick, I'm not fussy) - you
missed the fact that this doesn't make it a quote.

Interesting. You seem to misunderstand on purpose! I just
stumbled onto this post and it makes no sense whatever! By Making
a quote of the pertinent part of what you are replying to, (AND
YOU MAKE IT A QUOTE BY INSERTING " " ) then someone can understand
what you say in context!

The reason only two responses were made, simple lack of any
information whatever in the post!

Easy way.... DON'T use Goggle Groups on the Newsgroups! They
suck!
 
This whole "argument" only arose in the last week or so due to Google's
new "improvements" to their newsgroup archives. I don't have a choice
over this. When I'm at work, I don't have a newsfeed and the only way I
could set one up is by running my own newsserver on a port that could
make it through the firewall. Whem I'm at home, 75% of the time I can't
reach my ISP's newsserver; I'm not sure why that is. So Google is my
best choice, and until very recently it was relatively problem-free.
 
R

Rich Grise

Jan 1, 1970
0
Besides the fact that there are apparently only two people who care (or
two people who read my posts - take your pick, I'm not fussy) - you
missed the fact that this doesn't make it a quote.

Well, you type "QUOTE ->" before it and "<- ENDQUOTE" after it. That will
make it a quote.

Good Luck!
Rich
 
R

Rich Grise

Jan 1, 1970
0
This whole "argument" only arose in the last week or so due to Google's
new "improvements" to their newsgroup archives. I don't have a choice
over this. When I'm at work, I don't have a newsfeed and the only way I
could set one up is by running my own newsserver on a port that could
make it through the firewall. Whem I'm at home, 75% of the time I can't
reach my ISP's newsserver; I'm not sure why that is. So Google is my
best choice, and until very recently it was relatively problem-free.

So, use google, AND USE COPY AND PASTE!

I've described, in detail, TWICE, how to do it.

I guess if you're stonewalling me, there's no reason for me to continue to
try to reply to you anyway.

Good Luck,
Rich
 
J

jtaylor

Jan 1, 1970
0
I hate this too, but the below works for me:

Click "Show Options"

Click "Reply" in the now shewn options. You'll get what you want. Don't
forget to snip, and bottom the at post.
 
Blame Google's new service. It's inconsistent and inconvenient.
I hate this too, but the below works for me:

I just worked out the secret. If you log in to write a reply and check
the "Don't ask for my password for 2 weeks" box, then all subsequent
replies use the non-quoting JavaScript text box. If on the other hand
you leave that box unchecked, then every time you post it will take you
to the old-style full-page posting with automatic quoting.
 
J

JeffM

Jan 1, 1970
0
[discussion about Google Groups blockquoted text]
I just worked out the secret.
...[don't] check the "Don't ask for my password for 2 weeks" box,
...[you will get]...automatic quoting.
[email protected]

Give that young man a silver wheel mouse.
 
B

BFoelsch

Jan 1, 1970
0
John Woodgate said:
I read in sci.electronics.design that Rich Grise <[email protected]>

Try that with one of those delightful through-hole parts that is all of

I was going to say.. Quitcherbitchen....I have GOOD color vision and I still
can't read a lot of the new resistors!! If I have any doubt I measure the
damn thing. I just bought some 1/2 watt metal film, and I never saw such a
sorry bunch of colors. Blue, gray and violet look like three different
colors of mud. Orange and brown both look like overheated yellow. White
looks gray. But the black is good.....

Bring back the good old Allen-Bradley colors. Better yet, we need a way to
put 1 watt sized bands on an 1/8 watt resistor!
 
P

Paul Hovnanian P.E.

Jan 1, 1970
0
Rheilly said:
[snip]

What you really need is an ammeter that under no current flow indicates '12
oclock' and for discharge the needle swings to the left, should the
conditions produce a charge to the battery the needle swings to the right. I
reckon this could really catch on if someone chooses to make such devices.
Even the colour blind could interpret that.

Its been done. I have one on my truck and I can't figure out why auto
mfgs stopped incorporating them into dashboards.

I an see why someone might want to save some real restate on a
motorcycle instrument cluster by going with an LED.
 
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