Sound card as digital Oscope
Biggest problem with this is that the sound card is filtered to audio
band only. And for testing audio circuits, I'd want an Oscope that
goes to at least 60KHz, 1MHz better.
Why? Because:
1. The Oscope bandwidth always needs to be larger than the waveform
under test. A standard analog Oscope is useable far beyond it's rated
bandwidth. A sound card is low pass filtered rather abruptly. Anything
other than a pure sine wave has harmonics, the first harmonic of a
square wave is 3x the original.
But you're thinking, Steve, I can't hear 3x 10KHz anyway, so who
cares? Simple- you won't be able to see it on a sound card, either,
but clipping at 10KHz will cause IM (Intermodulation Distortion) that
you -can- hear. IM is this: say you have a 12KHz and a 10KHz sine
wave, no clipping. Fine. You get 10KHz and 12KHz. Start clipping: now
they mix (just like in a superhet radio) and you not only get 30KHz
and 36KHz, you also get 2KHz. And some 6KHz, too. And in lesser
amounts, 8Khz, 4KHz, etc. Gets messy, doesn't it?
But you won't see that clipping on a sound card.
2. Parasitics. You'll never see parasitic oscillations as they
typically happen way beyond 20KHz. An audio amp not carefully
designed, or improperly repaired may go into destructive parasitic
oscillations only under heavy clipping, or with loads that are too
high impedance. Even some well designed amps (usually very high power
amps) will go into parasitic oscillations and destroy themselves if
run without speakers or dummy loads attached.
Now if you have an Amiga... there are several projects on Aminet using
off the shelf ADC chips. So that even a relatively old Amiga can be
used as a digital Oscope up to 85 or 100KHz. There are some FFT real
time analyzers for the Amiga, but they require a faster Amiga and most
sample only at audio frequencies.
The TestGear files have some very good test equipment projects using
Amigas.
Fast sampler project using the MAX153 which is capable of 1Msps. Of
course the Amiga can't go -that- fast through the parallel port:
Schematic of MaxSampler:
Data page for MAX153:
56KHz mono sampler:
A limitation of cheap computer based digital Oscopes has always been
the speed of the serial or parallel port. It's relatively easy to use
either port. USB and Firewire are much faster but a bit more complex
to interface to ADC chips that have simple serial or parallel interfaces.
I figured a tradeoff would be a PIC or other microcontroller with some
fast external RAM. Do a fast blind transfer of the output of a
parallel ADC into RAM, then a slower transfer from the RAM to the PC
Should be able to find some static RAM that is fast enough for a 5 or
10MHz digital Oscope. Sampling would have to occur at 2 to 3 times
that frequency. You could always interleave the RAM for speed.
Alien Steve
|
Re: home-made signal generator question
My 2 cents: ICL 8038 or MAX038. The ICL 8038 is discontinued, but last
I checked Mouser still has a few. The MAX038 is a bit more expensive
but as I recall takes less external circuitry. And goes up quite a bit
higher.
The VCO capabilities of it mean you could also use it as a sweep
generator. Send a ramp wave into the VCO input of either of those
chips, the same ramp into the Horizontal (X) input of your scope,
output of the sign gen into the amp under test, and the output of the
amp into the vertical input of your scope.
Alien Steve
toggle quoted message
Show quoted text
-----Original Message-----
From: Murat Ceylan [mailto:hector@g...]
Sent: 16 April 2004 10:43
To: Electronics_101@...
Subject: [Electronics_101] home-made signal generator question
Hello Everyone,
I'd like to build a signal generator that is not too professional but
good
enough for general use i.e. that can produce sine, sawtooth and square
waveforms in 1-50kHz range or so with reasonable reliability. Do you
happen
to have any schematics, suggestions, assembly tips etc.?
Many thanks in advance,
Murat
--
NEU : GMX Internet.FreeDSL
Ab sofort DSL-Tarif ohne Grundgebühr:
_____
Yahoo! Groups Links
* To visit your group on the web, go to:
* To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...
<mailto:Electronics_101-unsubscribe@...?subject=Unsubscrib
e>
* Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service <> .
|
Re: Triac instead of relay ?
And that is what makes me say the current lags. Alien Steve --- In Electronics_101@..., Stefan Trethan <stefan_trethan@g...> wrote: I said several times now the red waveform is NOT something you will see on a scope.
It is what you get if you look at the furier analysis of the current.
Basically you can describe any periodic signal with a number of sine
signals with different
phase shift and amplitude.
the red one is the biggest one you would get, the first component of the furier analysis.
you can get it in hardware by filtering a signal with a lowpass which cuts everything above
the 50 or 60Hz of the mains. I don't want to do that because every filter has inductances or capacitances.
The furier components are there without a fiter anyway, and the first is strongest,
and it is the red sine.
st
|
Does anyone know of a supplier for SMD lqfp smd to .1 pad boards?
|
Re: home-made signal generator question
Hi
Murat..
?
Not
sure what you wanna use the signal generator for , but I used mine to fix audio
equipment..
I
downloaded? a program from the NET which uses my sound card. I was able to
change freq and amplitude as well as diffrent type of wave
forms.
?
I
could measure with Scope and then see how the amp was performing.. Pretty stable
on the output..
?
Hope
that help someowhat as an idea..
?
Thks
Gary
?
toggle quoted message
Show quoted text
Hello Everyone,
I'd
like to build a signal generator that is not too professional but
good
enough for general use i.e. that can produce sine, sawtooth and
square
waveforms in 1-50kHz range or so with reasonable reliability.?
Do you happen
to have any schematics, suggestions, assembly tips
etc.?
Many thanks in advance,
Murat
--
NEU : GMX
Internet.FreeDSL
Ab sofort DSL-Tarif ohne Grundgebühr:
|
Re: *.bmp Was: Triac instead of relay ?
you can download free irfanview.
i think it is irfanview.com.
you will love it.
ST
|
Re: Triac instead of relay ?
I said several times now the red waveform is NOT something you will see on a scope.
It is what you get if you look at the furier analysis of the current.
Basically you can describe any periodic signal with a number of sine signals with different
phase shift and amplitude.
the red one is the biggest one you would get, the first component of the furier analysis.
you can get it in hardware by filtering a signal with a lowpass which cuts everything above
the 50 or 60Hz of the mains. I don't want to do that because every filter has inductances or capacitances.
The furier components are there without a fiter anyway, and the first is strongest,
and it is the red sine.
st
toggle quoted message
Show quoted text
On Mon, 19 Apr 2004 16:17:27 -0700, Scott Thompson <electronguy@...> wrote: All this triac talk has got me thinking that I am going to need to perform some experiments myself. I've created a few magnetic drivers with MOSFETs, so I know how difficult inductors can be to drive, but I do not know how you got your red current waveform. I'm going to have to look at my scope for myself at the current/voltage relationship. If you're trying to charge a cap or an inductor, you would see a phase shift, but it doesn't make any sense that you would get a clean sinewave current waveform when you're only taking part of the voltage waveform.
Are you looking at an oscilloscope output? What is your test jig setup like?
Curious,
Scotty
----- Original Message -----
From: Stefan Trethan
To: Electronics_101@...
Sent: 4/18/2004 3:22:01 PM
Subject: Re: [Electronics_101] Re: Triac instead of relay ?
look at my attachment please.
i also can not believe there is reactive power but how is the phase shift
explained otherwise?
thanks
st
On Thu, 2 Jan 1997 18:52:49 -0600, Curtis Sakima <csakima@...> wrote:
I think we could be getting into a semantic war with this thing. So ....
instead of my talking anymore ... please ... everyone open up the *.bmp
attachment of this email. THIS .... is what I saw on the scope output of
the triac dimmer. The arrows indicate what moves as I dim the lamps up
and
down. The overall wave doesn't shift ... but that vertical line
(indicated
by the arrows) ... shifts left and right.
As the area under the curve varies ... so does the intensity of the
lamps.
I thought a picture might settle this.
Curtis
Yahoo! Groups Links
To visit your group on the web, go to:
To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
|
Re: Variable Resistor Using FETs
Send me the file first. and discuss what is Ur project let me see where I can help. --- Syed Hasan Rizvi <engrHasanRizvi@...> wrote: > Hi All, I am trying to search for a better way to design a
programmable analog
filter. I implemented a 2nd order Sallen&key filter
with DC adjust a while
back using AD8400 digital potentiometers.
I am looking for ideas to use a FET as a variable
resistor.
I am uploading the existing design "Filter with DC
adjust.jpg" in group
files.
Any suggestions or ideas..............
Regards,
Syed Rizvi
------------------------ Yahoo! Groups Sponsor
Yahoo! Groups Links
Electronics_101-unsubscribe@...
____________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now
|
On Mon, 19 Apr 2004 16:27:27 -0700, Scott Thompson <electronguy@...> wrote: The high-valued feedback resistor is perhaps causing a lot of phase shift because of the feedback capacitance, etc.
Try a 6.8 pF capacitor across your 2M feedback resistor.
Best,
Scotty
Where do you see a schematic or know the value of the feedback resistor? 2M feedback is really high, try to stay between 1k and 100k. maybe lower if you don't load the output with it (e.g. noninverting amp the resistor from inv to ground) Or use two stages if you can't fit that much gain in one. ST
|
Re: *.bmp Was: Triac instead of relay ?
Curtis
?
open it in Photo editor (standard with M$) and then save as jpg
?
Tony
?
>????From: "Curtis Sakima"
>Subject: *.bmp?? Was: Triac instead of relay ?
>
>Sorry.??At this point I only have what came with M$Windows .... and only
>Paint .... which draws in *.bmp format.
>
>Curtis
Find love today with ninemsn personals.
|
Murat: RE: home-made signal generator ..
Murat: Yes but how do you find out the wave type. I can help you if there is any transmission of wave required. U can either choose FM/AM transmitter to do that. OK tell me more on wher U have stopped. Elaborate it. Bye --- Murat Ceylan <hector@...> wrote: > Hello Everyone,
I'd like to build a signal generator that is not too
professional but good
enough for general use i.e. that can produce sine,
sawtooth and square
waveforms in 1-50kHz range or so with reasonable
reliability. Do you happen
to have any schematics, suggestions, assembly tips
etc.?
Many thanks in advance,
Murat
--
NEU : GMX Internet.FreeDSL
Ab sofort DSL-Tarif ohne Grundgeb???hr:
------------------------ Yahoo! Groups Sponsor
Yahoo! Groups Links
Electronics_101-unsubscribe@...
____________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now
|
Re: Att: Sudeep; Wireless transmission
I told U that I can build one. U can consult me
____________________________________________________________
Yahoo! Messenger - Communicate instantly..."Ping"
your friends today! Download Messenger Now
|
--- In Electronics_101@..., JanRwl@A... wrote: In a message dated 4/19/2004 6:57:05 PM Central Standard Time,
signalsnatcher@y... writes:
Manhatten
It boggles my tiny, feeble mind that NOone, yet, has noted the spelling error in this word! It's all-"a's"; NO "e" !!!!!!!!!!!!!!!!!!! funny how Google offers 21,000 hits on Manhatten Project. funny how it hits 1,390,000 for Manhattan Project.... Dave
|
A few weeks ago, I had some help on some questions on a electronics
quiz. Anyways, thanks Stephan.
I got the quiz back and thought I would post the entire quiz for all
to answer if they wanted. There is no need to post your answers,
this is just for your all information and enjoyment.
I will post the answers to each tomorrow. Hopefully some will enjoy
and learn from it.
1. Which test instrument is designed to measure current, voltage,
and resistance?
a) A DC Power supply b) A multimeter
c) Function generator d) An Oscilliscope
2) Which test instrument is used to generate waveforms of a certain
shape and frequency?
a) DC power supply b) A multimeter
c) Function generator d) An Oscilliscope
3) Which instrument is designed to to deliver a DC voltage for
expermentation?
a) DC power supply b) A Multimeter
c) Function generator c) An Oscilliscope
4) Which test instrument is used primarily to display the shape and
spacing of electrical signals?
a) DC power supply b) A Multimeter
c) Function generator d) An Oscilliscope
5) The Oscilliscope can be used to measure:
a) AC and DC voltage b) Frequency c) Rise and fall times
d) Duration e) All of the above
6) How many electrons are present in the valence shell of a
semiconductor?
a) 2 b) 4 c) 6 d) 8
7) A hole is consdiered to be a:
a) Negative charge carrier b) Positive charge carrier
8) What are the majority carriers in an N-type material?
a) Holes b) Electrons
9) What are the majority carriers in P-type material?
a) Holes b) Electrons
10) What is the approximate barrier potential for a silicon diode?
a) 0.3V b) 0.4V c) 0.7V d) 2.0V
11) The junction diode can be found in a __________ circuit that is
used to convert AC to DC.
a) Rectifier b) Modulator c) Demodulator d) Digital Logic
12) The four main blocks of a power supply, in order are:
a) Rectifier, Transformer, Filter, Regulator
b) Transformer, Filter, Rectifier, Regulator
c) Transformer, Rectifier, Filter, Regulator
d) Transformer, Filter, Regulator, Rectifier
13) A _______ diode can be used as a voltage regulator.
a) LED b) Photodiode c) Zener d) Schottky
14) The reverse ______ a zener remains constant while the reverse
zener _______ varies.
a) Current of; voltage b) Voltage across; current
15) What resistance should a good rectifier diode have when it is
forward biased?
a) High b) Low C) Infinite d) Any of the above
16) What resistance should a good rectifier diode have when it is
reversed biased?
a) High b) Low c) Zero d) Any of the above
17) When a diode is on under normal operating bias conditions, you
can assume it be ______ to the DC and _______ to the AC.
a) a(n) essentially constant voltage; a(n) low value resistance
b) a(n) low value resistance; a(n) essentially constant voltage
18) A ______ diode would typically be used in a power supply as a
power indicator.
a) Rectifier b) Light emitting c) Zener d) Junction
19) A ________ diode would be typically used as a regulator.
a) Rectifier b) Light emitting c) Zener d) Junction
20) To forward bias a PN junction, place a relative _______
potential to the N material and a relative ________potential to the
P material.
a) Negative; positive b) Positive; Negative
21) To reverse bias a PN junction, place a relative ______ potential
to the N material and a relative _______ potential to the P material.
a) Positive; Negative b) Negative; Positive
22) Silicon has a valence of _______.
23) In a filtered bridge power supply, the DC output voltage is
approximately normal but the ripple is approximately twice as large
as normal. What is the most probable cause?
a) Open Capacitor b) Shorted diode c) Open diode d) Open Load
24) In a filtered full-wave center tapped power supply, the expected
DC output voltage is 24 volts. The measured output voltage is 15.3
volts, what is the most probable cause?
a) Open capacitor b) Shorted diode c) Open diode d) Open Load
25) When a filtered capacitor is properly inserted in a rectifier
power supply, the average DC out will ______, the AC ripple out will
_______.
a) decrease; increase b) increase; increase
c) increase; decrease d) decrease; increase
That's it. Will post answers tomorrow sometime.
|
Re: *.bmp Was: Triac instead of relay ?
In a message dated 4/19/2004 8:47:53 PM Central Standard Time, csakima@... writes:
Sorry.? At this point I only have what came with M$Windows .... and only
Paint .... which draws in *.bmp format.
Convert to *.jpg once drawn or downloaded.
|
In a message dated 4/19/2004 6:57:05 PM Central Standard Time, signalsnatcher@... writes:
Manhatten
?
It boggles my tiny, feeble mind that NOone, yet, has noted the spelling error in this word!? It's all-"a's";? NO "e" !!!!!!!!!!!!!!!!!!!
|
During World War II the Germans invented an anti-shipping mine that exploded when it detected the natural magnetic field of a ship's hull overhead.? This mine could?sit on the sea floor so that it could not be?swept by normal methods?and posed a serious threat to Allied naval and merchant vessels.
?
British scientists discovered that if?a ship's hull was demagnetised by passing a large coil with an AC current over the hull, the ship would not explode these "magnetic mines".? This process, called "degaussing" was experimented with on US?and UK warships but soon applied to all Allied ships.? US sailors were told that degaussing made a ship "invisible to magenetic mines", according to my great-uncle Ed who, though an Aussie, served in the US merchant marine and now lives in California.
?
I think this is where the story came from.? Remember most people who served in the navies of that time had an education equivalent to primary (elementary) school Year 5 by today's standard.? It was war, there was a great deal of secrecy and, of course, this is when the rumour mill gets to work.
?
At that time Einstein was busy at Princeton making contributions to the Manhatten Project (the Atom Bomb), but Tesla, great man though he had been, was in his declining years and had done little scientific work for years.? He had suffered a serious mental collapse some time before and was living on his friends' charity and seems to have had occasional delusional episodes.?
?
Telsa still read the scientific literature and gave regular newspaper interviews during which he often?leaked more secrets than he should have.? Since his homeland was under German occupation he was technically an enemy alien.? In the UK he would have been placed, at least, under house arrest.? When he died the FBI seized his papers, not because he had invented some secret weapon, but because he was a nuisance to a nation at war.? His indiscretions seem to have been the source of many rumours, like this one.
?
There was a reunion of the salors who had served in the USS Philadelphia in 2002.? A journalist from the Fortean Times asked them about the Philadelphia incident but they all agreed that the story was untrue.? I understand it wasn't much of a party.? They were all older guys and they faded early...
Stefan Trethan wrote:
I would say if there was something done it is gone wrong i expect.
You can't make money with something not working (and possibly being
dangerous).
They wouldn't tell us i reckon.
I really see not much positive use for this technology, we shouldn't need
to hide things, should we?
ST
>
> There would be too much money to be made from its use. If it did exist,
> people would likely want to use it. As they found how valuable it was,
> they would
> use it more. It would quickly become "visible".
>
>
> Rick Sparber
>
> rgsparber@...
>
> My Web Site:
> rgsparber.fifthprime.com
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Electronics_101/
<*> To unsubscribe from this group, send an
email to:
Electronics_101-unsubscribe@...
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
- Communicate instantly..."Ping" your friends
today!
|
The high-valued feedback resistor is perhaps causing a lot of phase shift because of the feedback capacitance, etc.
?
Try a 6.8 pF capacitor across your 2M feedback resistor.
?
Best,
Scotty
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: 4/19/2004 12:58:02 PM
Subject: [Electronics_101] signal oscillation
I am working on a high-gain current-to-voltage amplifier. I need to
convert a very low pulsed current signal (100 microsec, into a voltage signal (>10 mV) that I can read from the scope. I
tried the amplifier using a low-gain (0.2 V/microamp) setting, and it
works ok. When I tried it with a higher gain (2 V/microamp),
oscillations (~10 microsec, regular amplitude) showed up on the scope
display. I'd like to fix that, but don't know how. I need some help,
if you know how to fix it and what is the cause of that, please let
me know. Thanks!
|
Re: Triac instead of relay ?
All this triac talk has got me thinking that I am going to need to perform some experiments myself.? I've created a few magnetic drivers with MOSFETs, so I know how difficult inductors can be to drive, but I do not know how you got your red current waveform.? I'm going to have to look at my scope for myself at the current/voltage relationship.? If you're trying to charge a cap or an inductor, you would see a phase shift, but it doesn't make any sense that you would get a clean sinewave current waveform when you're only taking part of the voltage waveform.
?
Are you looking at an oscilloscope output?? What is your test jig setup like?
?
Curious,
Scotty
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: 4/18/2004 3:22:01 PM
Subject: Re: [Electronics_101] Re: Triac instead of relay ?
look at my attachment please.
i also can not believe there is reactive power but how is the phase shift
explained otherwise?
thanks
st
On Thu, 2 Jan 1997 18:52:49 -0600, Curtis Sakima wrote:
> I think we could be getting into a semantic war with this thing.? So ....
> instead of my talking anymore ... please ... everyone open up the *.bmp
> attachment of this email.? THIS .... is what I saw on the scope output of
> the triac dimmer.? The arrows indicate what moves as I dim the lamps up
> and
> down.?? The overall wave doesn't shift ... but that vertical line
> (indicated
> by the arrows) ... shifts left and right.
>
> As the area under the curve varies ... so does the intensity of the
> lamps.
> I thought a picture might settle this.
>
> Curtis
|
On Mon, 19 Apr 2004 19:54:47 -0000, ktauyeung <ktauyeung@...> wrote: I am working on a high-gain current-to-voltage amplifier. I need to
convert a very low pulsed current signal (100 microsec, <nanoamp)
into a voltage signal (>10 mV) that I can read from the scope. I
tried the amplifier using a low-gain (0.2 V/microamp) setting, and it
works ok. When I tried it with a higher gain (2 V/microamp),
oscillations (~10 microsec, regular amplitude) showed up on the scope
display. I'd like to fix that, but don't know how. I need some help,
if you know how to fix it and what is the cause of that, please let
me know. Thanks!
maybe try a second stage. ST
|
Steven AE7HD