Chip with simple program for Toy

Saran wrote:
Thanks a ton, John. It is conceptually clear now.

I have one question, how do we know how much current we have to
generate from a current mirror to bias a transistor. I know this is a
vague question, what I mean is, the gate capacitance determines the
rate at which the gate will be charged, right? So, are the gate
capacitances values standard for different transistors? Where are they
available from?
The gate capacitance is as low as the maker knows how to make it, and
the drain conductance is as high as the maker can make it. We are
stuck with what is available based on physics and the state of
technology at the time the device was made. If they make the
transistor larger, to raise the drain current, the gate capacitance
goes up. If they make the transistor smaller to shrink the gate
capacitance, the drain current goes down. So the details of gate
insulation thickness, channel doping profiles, and lots of other
details are the difference between the best combination and average
(or below average) performance. This is what keeps chip designers
working overtime and forever.

For instance, in an example, if the author says that a current mirror
outputs constantly 200nA to the input of the gate of some transistor
M1, he means that the gate voltage is being maintained constant
(unchaged) with this small current. The exact values, I assume, can be
obtained from the specific data sheets are manuals.
If the circuit is logic, the current source (not usually a mirror, but
just a common source amplifier) never holds the gate biased half way
on, but is always either saturated full on, full off, or is
transitioning between those saturation values as fast as it can charge
the gate capacitance.

For analog circuits (like opamps) there are usually two current
mirrors battling it out, one trying to charge the gate up and one
trying to dump the charge out of it, and in the steady state case, one
current mirror is pouring current into the other one, and the gate
charge is sitting unchanging somewhere at a middle voltage. Then the
two mirrors unbalance from a change in the signal and the gate swings
to another voltage, till the feedback rebalances the mirrors to a
standstill.

For instance, in this simple opamp:
http://www.arky.ru/audio/sprav/datasheets/ca3130.pdf
Q3 and Q5 are a pull up current mirror (that supplies a constant pull
up current) and Q11 is a variable pull down current source dependent
on the balance of the two input voltages. The output of the opamp
(the drains of Q8 and Q12) depends on what voltage there is on the
gates of Q8 and Q12 when the pull up and pull down current sources on
their gates become equal and stop supplying either pull up or pull
down current to charge them. If those two currents are not equal, the
remainder will go into changing the gate voltage and the output
voltage will be in slew.
 
neil wrote:

"fpd" <foreignpigdogAThotmailDOTcom@nospam.com> wrote in message
news:42730cad_1@newsfeed.slurp.net...
neil wrote:
mnitin73@gmail.com> wrote in message
news:1114481060.688099.87690@l41g2000cwc.googlegroups.com...
Can I connect the port to the rx pin of the 9 pin serial port and make
any sense? Are the 1553B interface cards standard or does it have to be
custom made depending on the equipment
Excalibur make 1553 interface cards but they are about Ł1500 each.
The data (as I recall, no doubt someone will correct/clarify...)
is a serial differential transformer coupled stream, at 1Megbaud.
Each data word is 16 bits, with a couple of start and stop bits.
The words are grouped in messages, and sent under control of the bus
controller.
You may have a controller or remote terminal (slave device).
The voltage level ranges from 3 to 30 volts.
Probably difficult to get a com port to talk/listen.
hope this helps,
Neil

Neil C.? GE32?
I'm Neil from Chatham in Kent, England.
Work (currently) for BAE Systems.
Not sure what the GE32 is, so it's probably not me you're thinking of.
BAE - GoldExpress, perhaps.
 
mnitin73@gmail.com wrote:

Can I connect the port to the rx pin of the 9 pin serial port and make
any sense? Are the 1553B interface cards standard or does it have to be
custom made depending on the equipment
Try this 1553 introduction:
http://www.systran.com/ftp/literature/53/1553tdd.pdf
 
On 2 May 2005 09:32:44 -0700, "mjohnson" <crvmp3@hotmail.com> wrote:

Wow! thanks for doing drawing up that schematic. That was very kind of
you.

I do have a question, since the buzzer will be buzzing I need to
"absorb" the transitions between the buzzer oscilations. Functionaly,
I just need to know that the buzzer is going off. Is that the reason
for the .1 uF cap between the alarm and the rest of the circuit, to
absorb the oscilation and keep the voltage high for the duration of the
alarm?
---
No, that cap is to allow the pulses from the buzzer to get through to
the + input of the first comparator while blocking any DC on the
buzzer's output. With no input from the buzzer, The + input of the
comparator will be pulled up to the +5V rail and will be at a higher
voltage than the - input, so the output of the comparator will be
quiescently high, and the 0.1ľF cap on its output will get charged up
to +5V through the 1 megohm resistor. Since the output of the first
comparator is connected to the + input of the second comparator, the
voltage on that input will be higher than the voltage on the - input,
and the output of the second comparator will be quiescently high. The
100k ohm resistor on the output of the second comparator is used to
pull the output up to +5V and to provide a DC return for the 0.1ľF cap
on the output of the comparator. the other 100k ohm resistor is used
to pull the trigger input of the 7555 high and to provide a DC return
for the cap. The 1 megohm resistor and 2ľF cap are used to generate
the ~ 2s wide output pulse from the 7555, and the transistor is used
to turn on the relay when the output from the 7555 goes high.

How it works is that nothing happens until the alarm goes off, then
when it does a low going edge at the output of the 0.1ľF cap connected
to the buzzer will pull the + input of the first comparator lower than
the voltage on the - input, forcing the comparator output low. When
the comparator's output goes low, it immediately discharges the 0.1ľF
cap on its output, pulling the output of the second comparator low.
When that happens, the 7555's trigger input will be pulled low for
about ten milliseconds, causing the 7555's output to go high and start
the two second timeout period.

Now, as the pulse input from the buzzer continues to cause the + input
of the first comparator to vary about the switching threshold, (the
voltage on the - input) the output of the first comparator will
alternately discharge the 0.1ľF cap and then allow it to be recharged
through the 1 megohm resistor. While it discharges the capacitor
almost immediately, it will take much longer to charge back up to the
switching threshold through the 1 megohm resistor, so as long as the
buzzer is buzzing, the output of the second comparator will remain low
and only one 2s pulse will be issued by the 7555.

When the buzzer stops buzzing, the + input of the first comparator
will go high, the cap on the output of the first comparator will start
charging, and when it gets to about 4.5V the output of the second
comparator will go high, sending a positive pulse into the trigger
input of the 7555. This positive pulse will be clamped to the 5V rail
by the internal static protection diodes of the 7555 and, once that
happens, the circuit will be armed and will trigger with the next
output from the buzzer.

--
John Fields
Professional Circuit Designer
 
On Mon, 02 May 2005 09:20:51 -0700, phaeton wrote:

Anyone else have this issue, found a solution, or am i just not trying
hard enough? :p
Yeah - I have a lighted magnifier. :)

Cheers!
Rich
 
I found a low priced Inverter/Charger for $360.00 Don't know how good
they are but cheapest I've seen. If any one is interested.

http://inverterchargersite.com/

Allen
 
phaeton wrote:
Hi it's me again! 0_o

Do any of you have a hard time reading the color bands on resistors?
Well I am! When looking at the resistor itself:

1) I cannot see yellow bands against the beige resistor body at ALL.
This is less of a problem, as if i see no band, i can usually assume
it's yellow. White bands are very very faint.

2) Red and Orange. If one is right next to the other, sometimes i can
tell them apart, sometimes not. If there is only one or the other on a
resistor, i never can tell which it is.

3) Black, brown and violet. If black or violet is next to brown, i can
tell it's brown. If black or violet are next to each other, they both
look black. Brown by itself sometimes looks black, or occasionally
looks like red, depending on what is next to it.

What's funny, is that i'm not colorblind at all- anywhere else i don't
have this problem. In fact, i just recently saw an eye doctor and they
did the usual battery of "what number do you see in the dots" tests.
No problem. I was also fitted with glasses that correct my
astigmatism- everything is in focus now. I fiddled with electronics
somewhat about 10 years ago, and don't remember this issue.

I have one of those lil "resistor color code cheaters" from radio
shack's days of yore- turn the wheel and dial up the right colors, and
it'll show you the numbers. I don't have as much of a problem seeing
those colors, with the exception of black and violet (i distinguish
those by the numbers they bring up!).

All in all, when in doubt the DVOM comes out. I usually try to read
them first, and then measure them to see if i'm right. Sometimes i am,
sometimes i'm not.

I was suspecting my lighting- I haven't opened it up to look, but my
overhead light is probably a 100W incandescent. I took some resistors
of known values into the closet to view them under the flourescent
light. I expected the problem to be worse, but it's slightly better.
Not enough to help, but slightly better. I haven't tried sunlight yet-
it's been raining, snowing or cloudy for the last few weeks.

I might try a GE Reveal(tm) bulb:

http://www.gelighting.com/na/home_lighting/products/reveal_main.htm

Claimed to filter out "dulling yellows" and improve color clarity.
Dunno if it will help or hurt.

Anyone else have this issue, found a solution, or am i just not trying
hard enough? :p

Thanks for letting be dribble...

-jared
My ability to distinguish colors depends on the light source.
Sunlight best, Tungsten fair, compact fluorescents bad, sodium vapor
lights, forget it.

If you are using any kind of fluorescent, I suggest you look at its
reflection in a CD and see how its spectrum of color compares to
sunlight. Lots of shades are missing.
 
Your local auto parts store will have such a device for ~$10
e.g., http://tinyurl.com/cy2mb


Tony Christian wrote:
Can some point me in direction for a wiring diagram to build an Electronic
Amp Meter to read up to 50 amps charge/discharge? This for automotive use on
a 12V DC system.

Or does some know where one can buy one off the shelf?

Regards


Tony Christian
 
Anyone else have this issue, found a solution, or am i just not trying
hard enough? :p
Bright incandescent lights, take off my glasses, stick the resistor
about an inch away from my eye - maybe I can see then :).

(but be sure to check it in the multi-meter anyway before using it).
--
==>> The *Best* political site <URL:http://www.vote-smart.org/> >>==+
email: Tom.Horsley@worldnet.att.net icbm: Delray Beach, FL |
<URL:http://home.att.net/~Tom.Horsley> Free Software and Politics <<==+
 
mr_bonez_99@yahoo.com wrote:
Hi

I am just starting out in this whole field and I am looking for some
help. I would like to try to complete a simple project which will be
the foundation for a slightly more complicated project.

All I want to do is make a light(LED) go on when a motion sensor(IR -
PIR? Seems to be cheap and cheap is good) detects movement. If anyone
can point me in the direction of a tutorial or tell me what kind of
parts I need to get etc(obviously motion sensor + light <?led?>+ power
+ other stuff?)I would appreciate it. I have tried to find tutorials on
Google but have been unsuccessful, this may be because I am new to this
field and I don't know the "lingo" so I don't really know what to
Google.

Any help that anyone can offer will be appreciated.


Thank you

~Mr_Bonez
You can buy a motion detector light fixture at any hardware store.
They go on sale here for $7. Hard to imagine building one any cheaper.
That's less than you'd pay for shipping if you ordered parts.

X10 sells power line connected units and RF connected units.
I have in my hand a X-10 Powerhouse Model MS13A that is battery powered,
detects motion, turns on it's led, transmits codes to the X-10 wireless
RF receiver.

If you tried to build one from scratch, your biggest problems wouldn't
be electronic.
The ones I've seen work by using multiple Fresnel lenses to present
spatially displaced imges. As you move, those images slew across the
sensor which detects change. You'd have to learn about infrared
transparency of plastic materials, Fresnel lenses etc...then try to make
'em.

mike
--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Wanted 12" LCD for Compaq Armada 7770MT.
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/
 
Anyone else have this issue, found a solution, or am i just not trying
hard enough? :p
I use only 1% resistors and find it impossible to read the colors
against that blue-ish background! I just use a good DVM.

Steve J. Noll | Ventura California
| The Used Equipment Dealer Directory:
| http://www.big-list.com
| The Peltier Device Information Site:
| http://www.peltier-info.com
 
<mr_bonez_99@yahoo.com> wrote in message
news:1115069351.392967.211200@g14g2000cwa.googlegroups.com...
Hi

I am just starting out in this whole field and I am looking for some
help. I would like to try to complete a simple project which will be
the foundation for a slightly more complicated project.

All I want to do is make a light(LED) go on when a motion sensor(IR -
PIR? Seems to be cheap and cheap is good) detects movement. If anyone
can point me in the direction of a tutorial or tell me what kind of
parts I need to get etc(obviously motion sensor + light <?led?>+ power
+ other stuff?)I would appreciate it. I have tried to find tutorials on
Google but have been unsuccessful, this may be because I am new to this
field and I don't know the "lingo" so I don't really know what to
Google.

Any help that anyone can offer will be appreciated.


Thank you

~Mr_Bonez
Check out http://www.hobbyengineering.com/SectionS.html They have IR
sensors with lenses, plus other things as well. Prices are very reasonable
too.

Brian
 
On 2 May 2005 09:20:51 -0700, "phaeton" <blahbleh666@hotmail.com>
wrote:

Hi it's me again! 0_o

Do any of you have a hard time reading the color bands on resistors?
Well I am! When looking at the resistor itself:

1) I cannot see yellow bands against the beige resistor body at ALL.
This is less of a problem, as if i see no band, i can usually assume
it's yellow. White bands are very very faint.

2) Red and Orange. If one is right next to the other, sometimes i can
tell them apart, sometimes not. If there is only one or the other on a
resistor, i never can tell which it is.

3) Black, brown and violet. If black or violet is next to brown, i can
tell it's brown. If black or violet are next to each other, they both
look black. Brown by itself sometimes looks black, or occasionally
looks like red, depending on what is next to it.

What's funny, is that i'm not colorblind at all- anywhere else i don't
have this problem. In fact, i just recently saw an eye doctor and they
did the usual battery of "what number do you see in the dots" tests.
No problem. I was also fitted with glasses that correct my
astigmatism- everything is in focus now. I fiddled with electronics
somewhat about 10 years ago, and don't remember this issue.

I have one of those lil "resistor color code cheaters" from radio
shack's days of yore- turn the wheel and dial up the right colors, and
it'll show you the numbers. I don't have as much of a problem seeing
those colors, with the exception of black and violet (i distinguish
those by the numbers they bring up!).

All in all, when in doubt the DVOM comes out. I usually try to read
them first, and then measure them to see if i'm right. Sometimes i am,
sometimes i'm not.

I was suspecting my lighting- I haven't opened it up to look, but my
overhead light is probably a 100W incandescent. I took some resistors
of known values into the closet to view them under the flourescent
light. I expected the problem to be worse, but it's slightly better.
Not enough to help, but slightly better. I haven't tried sunlight yet-
it's been raining, snowing or cloudy for the last few weeks.

I might try a GE Reveal(tm) bulb:

http://www.gelighting.com/na/home_lighting/products/reveal_main.htm

Claimed to filter out "dulling yellows" and improve color clarity.
Dunno if it will help or hurt.

Anyone else have this issue, found a solution, or am i just not trying
hard enough? :p

Thanks for letting be dribble...

-jared
The old Allen-Bradley composition resistors still look great. The
cheap carbon-film imports have very vague and inconsistant color
codes.

John
 
In article <1115094135.540773.143100@g14g2000cwa.googlegroups.com>,
ngdbud@hotmail.com wrote:

i went to an electronics store today looking for high voltage
capacitors for building a marx generator,the lady behind the counter
was as confused as i am by the name spark gap capacitor. can anyone
tell me how these are any different if at all from regular capacitors,
and would they work for a marx generator?
No difference in function, but maybe a difference in construction - A
cap specifically intended for spark-gap use might be built a bit
"beefier" to avoid frying it with the high voltages that a spark gap
wants to run at, or with different materials so that its "dump" speed is
faster, but aside from that... <shrug> A cap is a cap is a cap, at least
as far as basic function is concerned.

Basically, it sounds like you're looking for a high voltage rating, high
capacitance unit. What voltage range are you expecting the spark gap to
fire at? Use that as a base, and look for something rated for at least
that high a voltage, if not higher, in the mFd/pFd range your tuning
calls for. Your main worry is probably going to be arcing between the
plates and the possible resulting "pop" (or maybe "KABOOM!", depending
on how much power you're running) that can result from exceeding the
breakdown voltage of the cap's dielectric material.

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See <http://www.sonic.net/~dakidd/main/contact.html> for full details.
 
On 2 May 2005 09:20:51 -0700, "phaeton" <blahbleh666@hotmail.com>
wrote:


Anyone else have this issue, found a solution, or am i just not trying
hard enough? :p
At the lab where I used to work, we had exactly this problem,
especially with those blue-bodied 1% resistors. One of the
guys came up with the idea of switching to daylight balanced
fluorescents, which completely solved the problem. It made
the reds jump out from the browns. The only thing was it
made the whole lab seem like perpetual dawn light. Hard to
explain, but I found this unsettling after a few hours.
(Lab had no windows. Maybe I had become part Morlock.)
We eventually went back to mostly regular fluorescents,
with the daylight tubes only over the main parts drawers.

Best regards,




Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator
 
"Don Bruder" <dakidd@sonic.net> wrote in message news:uqDde.220$T3.1500@typhoon.sonic.net...

<snip>

Basically, it sounds like you're looking for a high voltage rating, high
capacitance unit. What voltage range are you expecting the spark gap to
fire at? Use that as a base, and look for something rated for at least
that high a voltage, if not higher, in the mFd/pFd range your tuning
calls for. Your main worry is probably going to be arcing between the
plates and the possible resulting "pop" (or maybe "KABOOM!", depending
on how much power you're running) that can result from exceeding the
breakdown voltage of the cap's dielectric material.
Maybe the answer is hidding in this last sentence, it might be a cap with
two safety electrodes (air gap) that discharge when voltage comes close
to maximum allowed voltage for that cap thus protecting the cap from
explosion/destruction.

--
Siol
------------------------------------------------
Rather than a heartless beep
Or a rude error message,
See these simple words: "File not found."
 
On Mon, 02 May 2005 06:05:15 +0000, Lord Garth wrote:

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:117b2rslf0s8ae9@corp.supernews.com...

"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> wrote in message
news:mcfde.30535$Jg7.29741@fe03.lga...
jim dorey wrote:

On Thu, 28 Apr 2005 04:52:02 -0300, Watson A.Name - "Watt Sun, the
Dark
Remover" <NOSPAM@dslextreme.com> wrote:

What I can't understand is why Tezas, with half the population of
California, has roughly the same number of prisoners sentenced to
death,
but Cailf has only one execution, Texas has 40. Must have
something to
do with lawyers.
:-/


maybe they're just bred to be less trusting of people who plead
innocence, the 'let god sort em out' mentality.

god is the one that forgives and gives them another chance, the
lawyers
in Texas just make sure the meeting takes place.

But _why_ the descrepancy between TX and Calif?



We mean what we say in Texas! Why bother to use sterile needles
though?
In case the executioner slips and sticks himself.

Cheers!
Rich
 
On 3 May 2005 06:44:08 -0700, hartlyuk@yahoo.com (hartly) wrote:

Thanks Andreww, and others.
My low current transformer does have 2 diodes in the circuit, but I
hadnt realized that they also restrict amps like a resistor does.
So that must be why it gives only 0.22 A
---
No. The reason you can only get 0.22 amps out of it is because of (to
a first approximation) the resistance of the primary and the
secondary. The diodes will drop a _voltage_ somewhere between 0.5V
and 1V depending on the current going through them. Read John
Popelish's reply again.

--
John Fields
Professional Circuit Designer
 
On 2 May 2005 21:22:15 -0700, ngdbud@hotmail.com wrote:

i went to an electronics store today looking for high voltage
capacitors for building a marx generator,the lady behind the counter
was as confused as i am by the name spark gap capacitor. can anyone
tell me how these are any different if at all from regular capacitors,
and would they work for a marx generator?

It's usually a ceramic disc cap that has a slit sawed a bit of the way
down from the top edge of the disk. Imagine cutting a small
rectangular slice out of a pie. When the voltage gets high enough, an
arc jumps between the exposed metalization layers, protecting some
other circuit component, or the cap itself, from overvoltage.

John
 
"SioL" <Sio_spam_L@same.net> wrote in message
news:MSLde.11878$F6.2402564@news.siol.net...
"Don Bruder" <dakidd@sonic.net> wrote in message
news:uqDde.220$T3.1500@typhoon.sonic.net...

snip

Basically, it sounds like you're looking for a high voltage rating, high
capacitance unit. What voltage range are you expecting the spark gap to
fire at? Use that as a base, and look for something rated for at least
that high a voltage, if not higher, in the mFd/pFd range your tuning
calls for. Your main worry is probably going to be arcing between the
plates and the possible resulting "pop" (or maybe "KABOOM!", depending
on how much power you're running) that can result from exceeding the
breakdown voltage of the cap's dielectric material.

Maybe the answer is hidding in this last sentence, it might be a cap with
two safety electrodes (air gap) that discharge when voltage comes close
to maximum allowed voltage for that cap thus protecting the cap from
explosion/destruction.
yes thats what this is, its a capacitor with a built in spark gap in
parallel, it often looks like a totaly ordinary ceramic capacitor with a
slot machined into the top of it.

theyr often used for protecting high voltage electronics where even higher
voltages are used such as in CRT where the high voltage EHT might arc over
to other electrodes ocasionaly. youl find them on the base of most CRTs

not sure they have any use for a marx generator though.

Colin =^.^=
 

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