jw,

An electrician I am not.

Well, actually we electronics types sometimes jokingly call electricians,
Glorifies Plumbers, they love it. :-)

I was capturing video from a SVHS player/recorder
into a Matrox RT2000 break out box. Instead of having the audio
cables on the audio out jacks of SVHS, I had them on the input jacks.
Now I can't hear or capture audio. What happened?

OK, are you saying that you successful captured the audio and now it
doesn't work? Or that it never worked. Nothing you described give
me enough information to help you.

I thought I'd test the devices. I hooked my vcr back to the tv; it
works fine.

So the VCR.

I hooked up the dvd player to the computer. No audio.

Whoops, now we've changed gears, that's like an equation with
more than one unknown. So far we've verified that the VCR
audio is probably OK. But we don't necessarily know about the
DVD player or the computer line in. Am I correct in assuming
that your VCR test involved only the RF connection, i.e. to the
TV antenna input? If so the VCR audio output could still be
bad though this is unlikely. With the VCR working into the
TV set, try to set up the VCR so that instead of using it's tuner
it responds to the video audio input jacks. Then connect the DVD
to those jacks. That will confirm that the DVD machine is OK.
(I'm also assuming that the DVD is a separate player, not on
the computer.

Next, I took audio in jacks out of the Matrox and connected them to
my sound card. Audio. But very loud and I could'nt contol it with
volume settings. As I was clicking through the settings the audio
vanished. I still get audio from the system, but can't feed it into
the system from an external source.

You know the old computer voice response, "Not enough information
to compute."? Need more detail in each step, what do you mean 'clicking
through the settings, on the computer? Where? Audio from the system,
The computer?

Can someone explain this to me?

Not until you explain what you are doing more specifically.

I know I once wanted to hook up
speakers to my laptop and put them into the mic jack instead of the
output jack and the mic in the laptop has'nt worked since. Any help
on how I can fix all this would be greatly appreciated.

Let's stick with one problem at a time.

Jim

Hello. An electrician I am not. I have a problem and don't know who
to take it to. I was capturing video from a SVHS player/recorder
into a Matrox RT2000 break out box. Instead of having the audio
cables on the audio out jacks of SVHS, I had them on the input jacks.
Now I can't hear or capture audio. What happened?

I thought I'd test the devices. I hooked my vcr back to the tv; it
works fine. I hooked up the dvd player to the computer. No audio.
Next, I took audio in jacks out of the Matrox and connected them to
my sound card. Audio. But very loud and I could'nt contol it with
volume settings. As I was clicking through the settings the audio
vanished. I still get audio from the system, but can't feed it into
the system from an external source.

Can someone explain this to me? I know I once wanted to hook up
speakers to my laptop and put them into the mic jack instead of the
output jack and the mic in the laptop has'nt worked since. Any help
on how I can fix all this would be greatly appreciated.

Thanks.

Victor.

We are Veron and Vic , siblings from Malaysia.
Nice to meet you.

Same here. I am of the age group where being able to exchange messages with
people all over the world is still an exciting novelty. When I was a kid we
hardly ever made long distance telephone calls.

recently, I insert an old tape[ which is my favourite tape ] into the
VCR.
It automatically jumped out after I heard the processing of the clever
mechanism inside seems like the electronics inside do not let it go on ,

That's when you should have quit when you were ahead. :-) I would say that
the problem could still have been either the machine OR the tape. VCR's are
mechanical and electronic marvels. I used to repair record players and tape
machines and none was so to technically precise as the cheapest VCR. On the
other hand it doesn't take much to make a VCR 'eat' a tape.

maybe it is problematic tape.

Since it was an old one that's possible. A good idea when a tape acts up is
to try another, preferably new one. If it loads OK that's a clue that maybe
the first tape has a problem, but it may have just not loaded properly. In
any case you are forewarned that there might be a problem and you may not
want to just put the tape back in the machine.

But, It no longer works. Tapes inserted will not wind automatically onto
the rollers , it just stops there, So , I have to eject it .

What is wrong ?

Good question, hard to trouble shoot by remote control. An experienced VCR
repair person might have some ideas. A little dirt can jam up the mechanism
or lock the little limit switches that sense various tape conditions so they
no longer sense the condition they are supposed to sense. Also lubrication
sometimes helps but is best done by someone who knows what he'd doing since
you can lubricate the wrong part(s).

I do not trust my technicians here because, I had it repaired once
before. The technician here just left it for 2 months and, finally they
say that they cannot repair !!!!!

I was charged for the service. Then, the technician sent it to the
toshiba technician. I was told that IC chip inside was burnt out.

So, the total repair time took 3 months, and I was charged twice. and it
is not cheap for the IC chip.

So you have that problem too, it's typical of service people in the US for
any product. If all the service people who didn't know what they were doing
were laid end to end they would be much more comfortable. :-)

In the US most people don't spend money on repairs of this kind of equipment
because the newer machines are probably better anyway. If you can afford it I
would buy a new machine. For all their marvels VCR's are not easy to repair
and only people who don't know what they are doing will bother 'repairing
them'. Those who do know how, don't make any money because people just buy
new. We can buy VCR's now for less than $100. If you've had your machine for
four years and no failures until know, buy a new one if you can.

Jim

charlexus,

i want to make a project using a microprocessor or a microcontroller.
would you help me with an idea...

While this may not be the case, this sounds like the 'help me do my homework'
request which are usually rejected by lists like this one. First off, give us
an idea about what you know about microprocessors. Remember that these
devices require both hardware and software to function. Some people who know
about more than I do about them might suggest what is called a PIC device or
a STAMP device. These are designed to enable the user to create in a
relatively short time a microprocessor type circuit and program them quite
easily. My knowledge is more along the line of standard microprocessors,
like the Z80, the 6802, etc.

Do you have any kind of specific category in mind for a project. Something
that just demonstrates microprocessors, i.e. flashes LED's or do you want
something more ambitious. Keep in mind that ambition has it's down side. :-)

Jim

a_w_abate,

To the point where I built several kits including a COSMAC Elf 1802
computer.

Wow, that was my first computer too. I recall being quite excited when I
entered a sample program that filled a 16 bit register the did a loop of
decrements and turned on a little LED when it was finished. It took about a
second. I would have bought/built something more complex / complicated if I
had the loot, but as a family man I didn't have any spare cash for such
things.

Now I am challenged by OpAmps and negative voltage.
I do not understand how to generate a negative voltage

Nothing special about a negative voltage. As with all voltage
what matters is the reference. Let's say that you consider
the reference point on a flashlight cell is the negative
terminal, then the positive terminal is at + 1.5 V. Then let's
say you decide that the positive terminal is the reference,
Then the negative is - 1.5 V. With op amps they often use
two power sources, they ground the negative terminal of
the positive source, and ground the positive terminal of
the negative. Both supplies may be identical, only the
grounded (power supply common) terminals make them
positive or negative terminals.

(for differential inputs) from one power supply such as a car battery. I
am trying to build a small headphone amplifier and am just coming up
with noisy audio. I believe this is because I am not apply the
negative voltage correctly. help!

If you are using batteries, just connect one with it's negative terminal
as common, i.e. grounded. Connect the other battery with it's positive
terminal grounded. Now you have a common terminal, which does NOT
get connected to the op amp, and a negative supply and a positive supply,
which DO get connected to the op amp.

One feature of an op amp is it's very high input impedance. This is achieved
because of the dual supply. The output impedance is extremely low.
What is really weird is that in some configurations the input at the
actual op amp is actually low. The input impedance of the amplifier then
is equal to the input resistor.

Please don't anyone flame me on my op amp knowledge or lack thereof.
I haven't worked with them in awhile.

Jim

Hai,

We are Veron and Vic , siblings from Malaysia.
Nice to meet you.

We have a fully automatic Toshiba VCR , which is 4 years old.

recently, I insert an old tape[ which is my favourite tape ] into the
VCR.

It automatically jumped out after I heard the processing of the clever
mechanism inside seems like the electronics inside do not let it go on ,

maybe it is problematic tape.

But, I am too eager to watch to series show, I regreted to have inserted
it a few times inside again.

Finally, The tape stucks inside !!! I have to remove the cover in order
to cut out the tape twirling onto the rollers etc.

I thought everything will turn to normal after I recap the cover and put
everything back.

But, It no longer works. Tapes inserted will not wind automatically onto
the rollers , it just stops there, So , I have to eject it .

What is wrong ?

I do not trust my technicians here because, I had it repaired once
before. The technician here just left it for 2 months and, finally they
say
that they cannot repair !!!!!
I was charged for the service. Then, the technician sent it to the
toshiba technician.
I was told that IC chip inside was burnt out.

So, the total repair time took 3 months, and I was charged twice. and it
is not cheap for the IC chip.

Please help.

thank you ,

veron and vic

i want to make a project using a microprocessor or a microcontroller.
would you help me with an idea...

nak iklankan kereta anda ?
nak cari kereta ?
sila kunjumgi:

I was fairly interested in electronics when I was in high school. To
the point where I built several kits including a COSMAC Elf 1802
computer. However, I strayed from the hobby over the years but am
slowly returning. Now I am challenged by OpAmps and negative voltage.
I do not understand how to generate a negative voltage (for
differential inputs) from one power supply such as a car battery. I
am trying to build a small headphone amplifier and am just coming up
with noisy audio. I believe this is because I am not apply the
negative voltage correctly. help!

Thank you Doug, that answers my question.

Reji.



--- In Electronics_101@y..., Doug Hale <doughale@x> wrote:

Reji,
QPSK stands for Quadrature Phase Shift Keying
and
QAM stands for Quadrature Amplitude Modulation


Both send two bits at a time encoded in four different values
For QAM, the values are four different amplitude levels
and for QPSK the four values are four different phases.

If this isn't enough of an explaination, please ask for more

Doug Hale



Mr Reji George wrote:

Hi everyone!

I am a new memer to this group. I work in the Cable
Telephony area. Can anybody tell me the difference
between QPSK and QAM. I know that one is Phase
modulation ad another id=s amplitude modulation. Some
specific answers.

Thanks.

Reji

To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@y...



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johnmadelz,

I am a beginer of electronics world I would like to ask some

information about antenna that can accept better reception than
dipole antenna.

Your question is too general. What kind of reception are you looking
for, Television? I'm assuming TV, and the problem here is not dipole
vs. some other type but which kind of dipole. Television is either VHF
or UHF, in that US VHF is channels 2 through 12. UHF is the higher
channels. The problem with what we call 'rabbit ears', the little indoor
antennas that sit on top of the set is that they are often cheaply made
and sometimes come with funny little extra things that do little for
reception and only add to the cost.

TV reception is better now than it was in the 'old days'. Stations
have more power, receivers are more sensitive. Sensitivity helps
but the set still needs a strong signal. What makes things worse
is that the dipole is somewhat directional and TV stations are
generally each in a different direction from the antenna. I have
always found that 'rabbit ears' must be adjusted for optimum
results for each station. Better antennas are made but they
usually must be mounted on the roof of the building. That is
partly because they are usually large and bulky. In addition,
the best reception may requires several antennas, each pointed
in a different direction. This depends on how distant the
stations are and how divers their direction.

I know that u know better. this is the reason why I
ask better antenna,Because the place where my house is located is
very far from the transmitter and theres some mountain cover.

Now that is also a problem. The outdoor antennas most often used
for distant reception are called Yagis, they consist of many elements,
that make the antenna more sensitive in one direction than another.
These antennas won't correct for the effect of mountains, but
if you are getting some kind of signal now, they might help. I will
leave the rest of the answer to this problem to someone who has
worked more recently with TV antennas.

Jim

purohit,

i want to use LCD with a auronomous system.
waiting for ur reply.

You have my permission. :-) Seriously, I don't know
the answer but I'm pretty sure that anyone who
does will want more information. Be more specific.

Jim

iman,

Could somebody teach me what is differencies between
ASCII text and Modbus,for inter-device communication.

Now quite frankly I haven't heard of Modbus. I can tell you
that ASCII, American Standard Code for Information Interchange,
is simply a numeric code for letters, numbers, a few special
characters and some control characters. ASCII is widely used,
probably the standard, in the US. I would think that it may be
the standard for the world now, to have to convert among
various codes in international message handling would seem
an herculean task. When comparing communication codes
there are a number of considerations. Back when this sort
of communication was far less reliable the EBCDIC code
was sometimes used because it was more easily error
checked. I have never worked in an environment where
EBCDIC was in use.

Other considerations might be, what kind of information
is being transmitted. I don't know what is done to ASCII
when special characters are required, ones that look
strange to us who are accustomed only to English.

I haven't answered your question, but at least you know that
your message was received. This forum seems to have people
of widely varied skills and knowledge, I'm certain that someone
will be able to help you. It might help if you told us the context
in which you know about the Modbus code.

Is there an interface for these?

If the only difference between two code is the numerical values
conversion is quite simple. A look up table is often used, the
position in the table for one code is matched with the position
in the other table. A program has two pointers, one pointed
at the start of each table. The first table is searched
while incrementing both pointers until a match is found.
Then the value pointed to by the second pointer is the
converted character. There may be some programmers
in the group who know a more sophisticated conversion
scheme. I've never needed one.

Jim

Mark,

Fuses aren't rated in power because the load on a fuse varies with the
circuit voltage. If you're an electrician in North America and only deal in
120v circuits, then indeed fuses could be rated in watts.

I think it would be confusing to rate fuses in watts at this late date. In
addition in circuits operating at different voltages one would have to do the
math to decide what current would blow the fuse. In electronic circuits a fuze
might be located in a 24 V circuit, a 10 V circuit, etc. And conceivably
designed to blow at the same current. If they were rated in watts someone would
want to use the supply voltage and the current rating, which of course would not
be correct. The fuses power rating would be I squared R, with R being the fuses
resistance. And then the resistance would have to be included on the fuse
package if not the fuse itself. It's hard enough to find the current rating on
some fuses. So it seems to me that a current rating is entirely logical and
certainly more convenient.

To confuse matters further, power doesn't melt the fuse wire: energy does.
Energy = power x time.

Why do you have to bring up those important little details that make your
argument so sound? :-) I think that sometimes we technicians adopt concepts
that are more convenient than accurate, then forget the 'truth' because we so
seldom address it. I don't doubt that some engineers do the same thing, but
their work is more likely to keep them 'honest.' Of course, 'your mileage may
vary.'

Fuse manufacturers provide a 'time-current'
plot to let engineers how long it takes the fuse to stop the current for a
particular value of overcurrent.

Everything you wanted to know about fuses but were afraid to ask. This is very
interesting but as a tech the closest I ever came to worrying how long it would
take a fuse to blow was when we used 'slo blo' types to prevent the fuse from
blowing when the unit powered up and the filter caps. were charging.

Laboratories that produce artificial lightning use thin (#24, bare, tinned)
wire to carry the lightning currents. The currents are very high--in the
thousands of amperes (ever hear of a kiloampere?) But the duration of
lightning currents is around 100 microseconds. Power x time = energy is
thus very small, and these utterly inadequate-looking wires work just fine.

Just thinking about such lighting flickering like that hurts my eyes. I guess it
would depend on the type of lighting device. What is the duty cycle?

A good example of a truly strange fuse is the old VW fuse. Had a ceramic
body with the fuse wire on the outside.

I've seen lots of ceramic bodied fuses, never gave them much thought except that
they were not as easy to check for continuity.

Nobody ever explained why they were made this way, though
it's possible that the fuse wires were replaceable. Industrial fuses are
often made with replaceable wires.

We called them replaceable links, since the ones I've seen were not wires but
flat sheets. As big as they were I'm sure that the links were less costly than a
whole fuse, they were easy enough to replace.

something that you'll run into in some first-year electronics courses.
You're given a roll of fuse wire whose resistance is r/x ohms per meter, and
which will melt when its temperature reaches 200 degrees C. You're asked to
come up with a fuse that will blow when its current reaches 10 amperes. You
have to know the heating characteristics of the wire to solve the problem.
Generally it's easier to just experiment.

I'm afraid none of my colleges ever gave such a task. We never gave fuses much
thought except that they blow at the rated current and that they should always
be replaced by the correct rated fuse.

JIm

Look the main thing is that you know that we have four
ports in the 89C51 , port0 is being used by me for the
multiplexed address and data bus for addressing the
6264 external data memory okay now the thing is that I
am only going to use the RAM and use it simultaneously
as code memory ( ROM ) so I won't be using any
external EPROM , now I am going to interface the ADC
0808 with it too but I don't know if I can use the
port0 with it or not or do I have to use port1 for
this purpose and if I do use the port1 then how am I
going to generate the address at that port , and tell
me the analog inputs that will be selected by the
three address inputs , will they have to be decoded
too and how will I do that an example would be really
helpful and the start conversion and End of conversion
pins how will these pins function as how will they be
selected , the reference voltages and where will the
connections be made to the microcontroller . Also I
will need the implementation of the MAX232 IC with
this circuit for serial communications so please
information regarding that IC into this circuit would
be really helpful , I know I am asking a lot but
please I would be very much obliged if you could help
me . Thanking you in advance .

Nabeel.


__________________________________________________
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Make a great connection at Yahoo! Personals.

d,

The software to program the PIC or the program itself?

Oh, so the device is always a heartbeat away from it's father. :-)
Interesting idea. I should think then that most programs are far
smaller than the development system on the chip.

write your assembly program in - it's great, you can do all the good
debug/simulation stuff in it. It compiles to a common format hex file.

Assembly, OK, I think I keep getting the Stamp and the Pic confused.
I was thinking BASIC. And of course the final program has to be binary
rather than hex doesn't it. Does a HEX file have any meaning in this
case?

Jim

heros,

or that the length of a wire has nothing to do with resistence
- mark

But I do find it surprising that one who likes to get things stated

correctly does not want a wire to be called a resistor!!

Since these quotes are all mixed up and shortened I don't know who said what
and for certain what he said. Here's my parting shot on the fuze, resistor,
etc. topic.
I was wrong when I originally said that a fuze has no resistance, and of
course the resistance is required for it to fuze, i.e. blow, when it's rated
current passes through it. That something has resistance doesn't make it a
resistor. If it did we'd have to call everything that is not an insulator a
resistors, transformers, wires, fuzes, etc. A resistor is not simply a device
that has resistance but one in which resistance is utilized as part of the
circuit design, to achieve a voltage drop when connected in series, to bypass
current in a device when in parallel, i.e. shunt like the old D'Arsonval
(SP?) analog meters when used to measure current. Someone earlier said that
CMOS devices actually no longer use Metal, I don't know whether that is so,
but we don't stop calling them CMOS, which may be why I didn't know that
metal is no longer used in their manufacture.

Anyway, that's my swan song on the issue.

Jim

Kevin,

I think you are thinking of "magneto-striction"-

Now there's a term I haven't heard in a long time.

Jim

开云体育

--- In [email protected]@.... wrote:

hii alanblumlein!

I am a beginer of electronics world I would like to ask some

information about antenna that can accept better reception than
dipole antenna.I know that u know better. this is the reason why I
ask better antenna,Because the place where my house is located is
very far from the transmitter and theres some mountain cover.

kindly send an information that includes measurements,spacing,
size of the tubes to be used, and other needful
spicification If you really want to learn about



best wishes
ronie madelo