Oscilloscopes

RogerN
Guest

Sun Feb 07, 2010 11:31 pm

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

RogerN

D Yuniskis
Guest

Sun Feb 07, 2010 11:57 pm

RogerN wrote:

Quote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog

But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

Quote:

connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

You might look into an older logic analyzer "for mostly digital
circuits". Often, the cost of shipping is the biggest expense! :>

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

Rich Webb
Guest

Mon Feb 08, 2010 12:29 am

On Sun, 7 Feb 2010 15:31:46 -0600, "RogerN" <regor_at_midwest.net> wrote:

Quote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

"The" AVR scope? Hard to comment on it, knowing only that...

In general, though, USB-based scopes typically don't have particularly
high sample rates. I'd suggest looking into one of the smaller "real"
digital 'scopes, such as Instek or Rigol. There was a loooong discussion
on this back in December in this group with the subject "A good digital
oscilloscope?" (As you may imagine, this comes up fairly often here.)

A USB logic analyzer, on the other hand, is a useful gadget. I've been
using an Intronix for years and wouldn't go anywhere without it. Overdue
for a new model, though. http://www.pctestinstruments.com/

--
Rich Webb Norfolk, VA

Adrian Jansen
Guest

Mon Feb 08, 2010 12:53 am

RogerN wrote:

Quote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

RogerN

I got one of the Rigol DS1052E scopes from:

Hongkong Capital International Electronics Co., Ltd.

http://www.hkcapital.en.alibaba.com <http://www.hkcapital.en.alibaba.com/>
http://www.dealexcel.com <http://www.dealexcel.com/>
------------------------------------------------------------------------
Tel: 0086-755-83464576
Fax: 0086-755-83462980
Mobile phone:008613554847019
ADD:9A45 Square SaiGe HuaQiang North Rd Futian
District ShenZhen
China
Email :hkcapital_at_yahoo.cn
MSN:taoxiaofang2008_at_hotmail.com
SKYPE :hkcapital.alibaba

Good price and delivery.

Works well.

I also looked at various USB scopes etc, but a stand-alone bench
instrument still beats any PC based unit IMHO.
--
Regards,

Adrian Jansen adrianjansen at internode dot on dot net
Note reply address is invalid, convert address above to machine form.

mike
Guest

Mon Feb 08, 2010 2:46 am

RogerN wrote:

Quote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

RogerN

Go to a ham-radio swapmeet and pick up a Tektronix 465 or thereabouts.

The 7000 series is dirt cheap too...but you probably have to replace
a shorted tantalum cap on the plugin backplane board. EVERY dead one
I've bought had this problem.
Many other similar scopes are quite useful and cheap.

Bottom line, get a $20 analog scope and use it until you figger out what you
really want.

RogerN
Guest

Mon Feb 08, 2010 4:40 am

"Rich Webb" <bbew.ar_at_mapson.nozirev.ten> wrote in message
news:oueum59k7pbekmb7tfdbrnsut71epujn36_at_4ax.com...

Quote:

On Sun, 7 Feb 2010 15:31:46 -0600, "RogerN" <regor_at_midwest.net> wrote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was
looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope
would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

"The" AVR scope? Hard to comment on it, knowing only that...

In general, though, USB-based scopes typically don't have particularly
high sample rates. I'd suggest looking into one of the smaller "real"
digital 'scopes, such as Instek or Rigol. There was a loooong discussion
on this back in December in this group with the subject "A good digital
oscilloscope?" (As you may imagine, this comes up fairly often here.)

A USB logic analyzer, on the other hand, is a useful gadget. I've been
using an Intronix for years and wouldn't go anywhere without it. Overdue
for a new model, though. http://www.pctestinstruments.com/

--
Rich Webb Norfolk, VA

Here's some of the stuff I was looking at, some stand alone, some use PC:

http://www.youtube.com/watch?v=fxViYQ5WWOE

http://www.fpga4fun.com/digitalscope.html

http://cgi.ebay.com/Pocket-Oscilloscope-Kit-Portable-Scope-Handheld-Probe_W0QQitemZ160400610559QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item25589f14ff

But I thought this looked pretty nice:
http://cgi.ebay.com/Tektronix-2465-Four-Trace-300-MHz-Oscilloscope_W0QQitemZ140380514036QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item20af54a6f4

RogerN

D from BC
Guest

Mon Feb 08, 2010 7:01 am

In article <jfmdnTGV1t7WrPLWnZ2dnUVZ_vSdnZ2d_at_earthlink.com>,
regor_at_midwest.net says...

Quote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

RogerN

Ugh...
Spend at least over $1500.
Maybe Tektronix will nail up a chief scope engineer on a cross so that
you don't feel bad about spending lots of money on a scope.

D Yuniskis
Guest

Mon Feb 08, 2010 10:17 am

miso_at_sushi.com wrote:

Quote:

On Feb 7, 1:57 pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.
You might look into an older logic analyzer "for mostly digital
circuits". Often, the cost of shipping is the biggest expense! :

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

Ah, yes. And, more importantly, any *micrograbbers* that
might be attached to the pods! Otherwise, you'll spend more
on *those* than the logic analyzer itself! :<

miso@sushi.com
Guest

Mon Feb 08, 2010 10:24 am

On Feb 7, 1:57 pm, D Yuniskis <not.going.to...@seen.com> wrote:

Quote:

RogerN wrote:
What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog

But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.

You might look into an older logic analyzer "for mostly digital
circuits". Often, the cost of shipping is the biggest expense! :

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

Robert Roland
Guest

Mon Feb 08, 2010 11:11 am

On Mon, 08 Feb 2010 01:17:22 -0700, D Yuniskis
<not.going.to.be_at_seen.com> wrote:

Quote:

*micrograbbers* that
might be attached to the pods! Otherwise, you'll spend more
on *those* than the logic analyzer itself!

Depending on your needs, these might work:

http://www.dealextreme.com/details.dx/sku.8391

They're not spectacular in quality, and they're too big for the really
tiny applications, but they do work, and the price is not bad.
--
RoRo

mike
Guest

Mon Feb 08, 2010 11:29 am

miso_at_sushi.com wrote:

Quote:

On Feb 7, 1:57 pm, D Yuniskis <not.going.to...@seen.com> wrote:
RogerN wrote:
What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
But, your *digital* stuff *will* be "high frequency" (at least
considerably higher than the analog examples you mentioned)

connections to the microcontroller, maybe some SMPS circuits. I was looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.
You might look into an older logic analyzer "for mostly digital
circuits". Often, the cost of shipping is the biggest expense! :

Of course, it also depends on the types of problems you are
trying to troubleshoot with the device...

If you get a used logic analyzer, make sure it has the "pods". I'm
simply amazed at how the box and pods get separated.

I asked that question once. Turns out that anything in a big box

is an instrument. The other stuff goes in the wire recycle box.
By the time it gets to anybody who cares about it, it's too late.

Just look around the lab. Anything not in use has it's probes in
a drawer somewhere.

Another factor is that if the recycler does know what she's doing,
she knows that probes get separated. The probes are much easier to sell
and bring more profit than the main box.

Bargain hunters will gladly pay $50 for a box and then another $200
on EBAY for broken probes, but they wouldn't pay $200 for the whole thing
working.
Simple matter of supply/demand/greed/frugality...

mike
Guest

Mon Feb 08, 2010 12:25 pm

RogerN wrote:

Quote:

"Rich Webb" <bbew.ar_at_mapson.nozirev.ten> wrote in message
news:oueum59k7pbekmb7tfdbrnsut71epujn36_at_4ax.com...
On Sun, 7 Feb 2010 15:31:46 -0600, "RogerN" <regor_at_midwest.net> wrote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was
looking
at some microcontroller and fpga designs that you can get kits starting at
less than $100 and going up with more speed and features. Also, I see on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope
would
be a useful tool or if I would be wishing I went ahead and bought a nice
used scope on eBay.
"The" AVR scope? Hard to comment on it, knowing only that...

In general, though, USB-based scopes typically don't have particularly
high sample rates. I'd suggest looking into one of the smaller "real"
digital 'scopes, such as Instek or Rigol. There was a loooong discussion
on this back in December in this group with the subject "A good digital
oscilloscope?" (As you may imagine, this comes up fairly often here.)

A USB logic analyzer, on the other hand, is a useful gadget. I've been
using an Intronix for years and wouldn't go anywhere without it. Overdue
for a new model, though. http://www.pctestinstruments.com/

--
Rich Webb Norfolk, VA

Here's some of the stuff I was looking at, some stand alone, some use PC:

http://www.youtube.com/watch?v=fxViYQ5WWOE
That looks closest to a whole oscilloscope.

http://www.fpga4fun.com/digitalscope.html

Looks like an interesting toy for dedicated use. You'll be disappointed
with all the hassle of trying to use it as a general purpose scope.

Quote:

http://cgi.ebay.com/Pocket-Oscilloscope-Kit-Portable-Scope-Handheld-Probe_W0QQitemZ160400610559QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item25589f14ff

This is a TOY. 1MHZ sample rate...useless...

Quote:

But I thought this looked pretty nice:
http://cgi.ebay.com/Tektronix-2465-Four-Trace-300-MHz-Oscilloscope_W0QQitemZ140380514036QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item20af54a6f4

2465 is a VERY nice scope. Beware that they have a part that goes bad

and it's made of unobtanium. Only way to get the chip is to buy another
scope with a chip that hasn't failed YET. I sold mine while it was
still working.

Quote:

RogerN

Buy one of the toy scopes above if ANY of the following are true.

1 You are an experienced measurement tech and you know every measurement
you'll ever want to make and can verify that the unit can measure it.

2 You have too much free time on your hands, are tired of playing
solitaire and need a better time waster.

3 You want hands-on experience with the easy part of crappy digital
oscilloscope designs.

4 You want to spend more time futzing with the scope than working
on the project.

Never make your first scope a KIT unless #1 applies.
Never make your first scope a computer accessory unless #1 applies.
Never buy a digital (or analog) scope that doesn't let you view
what happens before the trigger event.

There may be exceptions, but a scope that doesn't have an input
attenuator and specified input capacitance is a poor choice.
Getting the signal into the acquisition unit and scaled appropriately
is HARD for the novice. Last thing you need is a scope that
smokes every time you touch the 12V power supply.

Don't buy a cheap scope on EBAY. Freight costs more than the scope
is work, even if you do get lucky and it works. A scope that's
guaranteed to work ain't gonna be cheap. Be especially wary of
"can't test it, don't have time to test it, don't have equipment
to test it". That's code for "broken".

I once asked about a "can't test it" scope on ebay. He accidentally
replied from an email account at the world's largest used test equipment
dealer. Seems that they sell the bad stuff out the back door on ebay.

If you want to make oscilloscope measurements, buy a real commercial
scope. I prefer analog for a first scope.

Find a local ham and put out the word you want a scope.
Most of us have more scopes than we can ever use.
Maybe you can borrow one 'till you figger out what you need.

Geography matters, but put a request for a scope on Craigslist or
equivalent.

You have a LOT more options if you are experienced, already have
a scope you can use to fix a busted new scope etc.
If you're a novice, go get a 30-40 year old analog scope CHEAP.

RogerN
Guest

Mon Feb 08, 2010 2:05 pm

"mike" <spamme0_at_go.com> wrote in message
news:hkooth$5qh$1_at_news.eternal-september.org...

Quote:

RogerN wrote:
"Rich Webb" <bbew.ar_at_mapson.nozirev.ten> wrote in message
news:oueum59k7pbekmb7tfdbrnsut71epujn36_at_4ax.com...
On Sun, 7 Feb 2010 15:31:46 -0600, "RogerN" <regor_at_midwest.net> wrote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was
looking
at some microcontroller and fpga designs that you can get kits starting
at
less than $100 and going up with more speed and features. Also, I see
on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope
would
be a useful tool or if I would be wishing I went ahead and bought a
nice
used scope on eBay.
"The" AVR scope? Hard to comment on it, knowing only that...

In general, though, USB-based scopes typically don't have particularly
high sample rates. I'd suggest looking into one of the smaller "real"
digital 'scopes, such as Instek or Rigol. There was a loooong discussion
on this back in December in this group with the subject "A good digital
oscilloscope?" (As you may imagine, this comes up fairly often here.)

A USB logic analyzer, on the other hand, is a useful gadget. I've been
using an Intronix for years and wouldn't go anywhere without it. Overdue
for a new model, though. http://www.pctestinstruments.com/

--
Rich Webb Norfolk, VA

Here's some of the stuff I was looking at, some stand alone, some use PC:

http://www.youtube.com/watch?v=fxViYQ5WWOE
That looks closest to a whole oscilloscope.

http://www.fpga4fun.com/digitalscope.html

Looks like an interesting toy for dedicated use. You'll be disappointed
with all the hassle of trying to use it as a general purpose scope.

http://cgi.ebay.com/Pocket-Oscilloscope-Kit-Portable-Scope-Handheld-Probe_W0QQitemZ160400610559QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item25589f14ff

This is a TOY. 1MHZ sample rate...useless...

But I thought this looked pretty nice:
http://cgi.ebay.com/Tektronix-2465-Four-Trace-300-MHz-Oscilloscope_W0QQitemZ140380514036QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item20af54a6f4

2465 is a VERY nice scope. Beware that they have a part that goes bad
and it's made of unobtanium. Only way to get the chip is to buy another
scope with a chip that hasn't failed YET. I sold mine while it was still
working.
RogerN

Buy one of the toy scopes above if ANY of the following are true.

1 You are an experienced measurement tech and you know every measurement
you'll ever want to make and can verify that the unit can measure it.

2 You have too much free time on your hands, are tired of playing
solitaire and need a better time waster.

3 You want hands-on experience with the easy part of crappy digital
oscilloscope designs.

4 You want to spend more time futzing with the scope than working
on the project.

Never make your first scope a KIT unless #1 applies.
Never make your first scope a computer accessory unless #1 applies.
Never buy a digital (or analog) scope that doesn't let you view
what happens before the trigger event.

There may be exceptions, but a scope that doesn't have an input
attenuator and specified input capacitance is a poor choice.
Getting the signal into the acquisition unit and scaled appropriately
is HARD for the novice. Last thing you need is a scope that
smokes every time you touch the 12V power supply.

Don't buy a cheap scope on EBAY. Freight costs more than the scope
is work, even if you do get lucky and it works. A scope that's
guaranteed to work ain't gonna be cheap. Be especially wary of
"can't test it, don't have time to test it, don't have equipment
to test it". That's code for "broken".

I once asked about a "can't test it" scope on ebay. He accidentally
replied from an email account at the world's largest used test equipment
dealer. Seems that they sell the bad stuff out the back door on ebay.

If you want to make oscilloscope measurements, buy a real commercial
scope. I prefer analog for a first scope.

Find a local ham and put out the word you want a scope.
Most of us have more scopes than we can ever use.
Maybe you can borrow one 'till you figger out what you need.

Geography matters, but put a request for a scope on Craigslist or
equivalent.

You have a LOT more options if you are experienced, already have
a scope you can use to fix a busted new scope etc.
If you're a novice, go get a 30-40 year old analog scope CHEAP.

Lot of good info there, thanks. I have a 10mhz leader single trace scope
that worked fine last time I tried it. Do you have any recommendations on a
used repairable scope? I've seen some recommend the Techtronics 465, since
a lot of what I plan to use it on is digital signals/communication, I
thought storage would almost be necessary.

RogerN

Rich Webb
Guest

Mon Feb 08, 2010 3:53 pm

On Mon, 8 Feb 2010 06:05:19 -0600, "RogerN" <regor_at_midwest.net> wrote:

Quote:

Lot of good info there, thanks. I have a 10mhz leader single trace scope
that worked fine last time I tried it. Do you have any recommendations on a
used repairable scope? I've seen some recommend the Techtronics 465, since
a lot of what I plan to use it on is digital signals/communication, I
thought storage would almost be necessary.

If you're interested in the information content of a data stream instead
of (or in addition to) the waveform, then you'll get a lot more mileage
out of a logic analyzer than a 'scope. The oscilloscope will let you
check the rise/fall times, envelope, eye diagram, etc. The analyzer will
let you read an I2C or CANbus conversation right off the screen without
a lot of tedious bit counting.

--
Rich Webb Norfolk, VA

mike
Guest

Mon Feb 08, 2010 4:02 pm

RogerN wrote:

Quote:

"mike" <spamme0_at_go.com> wrote in message
news:hkooth$5qh$1_at_news.eternal-september.org...
RogerN wrote:
"Rich Webb" <bbew.ar_at_mapson.nozirev.ten> wrote in message
news:oueum59k7pbekmb7tfdbrnsut71epujn36_at_4ax.com...
On Sun, 7 Feb 2010 15:31:46 -0600, "RogerN" <regor_at_midwest.net> wrote:

What's the best scope to get for the money for mostly digital circuits?
I'll have some analog but nothing real high frequency, like analog
connections to the microcontroller, maybe some SMPS circuits. I was
looking
at some microcontroller and fpga designs that you can get kits starting
at
less than $100 and going up with more speed and features. Also, I see
on
eBay you can get some nice looking Techtronics scopes for $350 or so, 4
channel digital, etc. Just wondering if something like the AVR scope
would
be a useful tool or if I would be wishing I went ahead and bought a
nice
used scope on eBay.
"The" AVR scope? Hard to comment on it, knowing only that...

In general, though, USB-based scopes typically don't have particularly
high sample rates. I'd suggest looking into one of the smaller "real"
digital 'scopes, such as Instek or Rigol. There was a loooong discussion
on this back in December in this group with the subject "A good digital
oscilloscope?" (As you may imagine, this comes up fairly often here.)

A USB logic analyzer, on the other hand, is a useful gadget. I've been
using an Intronix for years and wouldn't go anywhere without it. Overdue
for a new model, though. http://www.pctestinstruments.com/

--
Rich Webb Norfolk, VA
Here's some of the stuff I was looking at, some stand alone, some use PC:

http://www.youtube.com/watch?v=fxViYQ5WWOE
That looks closest to a whole oscilloscope.
http://www.fpga4fun.com/digitalscope.html
Looks like an interesting toy for dedicated use. You'll be disappointed
with all the hassle of trying to use it as a general purpose scope.

http://cgi.ebay.com/Pocket-Oscilloscope-Kit-Portable-Scope-Handheld-Probe_W0QQitemZ160400610559QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item25589f14ff

This is a TOY. 1MHZ sample rate...useless...

But I thought this looked pretty nice:
http://cgi.ebay.com/Tektronix-2465-Four-Trace-300-MHz-Oscilloscope_W0QQitemZ140380514036QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item20af54a6f4

2465 is a VERY nice scope. Beware that they have a part that goes bad
and it's made of unobtanium. Only way to get the chip is to buy another
scope with a chip that hasn't failed YET. I sold mine while it was still
working.
RogerN

Buy one of the toy scopes above if ANY of the following are true.

1 You are an experienced measurement tech and you know every measurement
you'll ever want to make and can verify that the unit can measure it.

2 You have too much free time on your hands, are tired of playing
solitaire and need a better time waster.

3 You want hands-on experience with the easy part of crappy digital
oscilloscope designs.

4 You want to spend more time futzing with the scope than working
on the project.

Never make your first scope a KIT unless #1 applies.
Never make your first scope a computer accessory unless #1 applies.
Never buy a digital (or analog) scope that doesn't let you view
what happens before the trigger event.

There may be exceptions, but a scope that doesn't have an input
attenuator and specified input capacitance is a poor choice.
Getting the signal into the acquisition unit and scaled appropriately
is HARD for the novice. Last thing you need is a scope that
smokes every time you touch the 12V power supply.

Don't buy a cheap scope on EBAY. Freight costs more than the scope
is work, even if you do get lucky and it works. A scope that's
guaranteed to work ain't gonna be cheap. Be especially wary of
"can't test it, don't have time to test it, don't have equipment
to test it". That's code for "broken".

I once asked about a "can't test it" scope on ebay. He accidentally
replied from an email account at the world's largest used test equipment
dealer. Seems that they sell the bad stuff out the back door on ebay.

If you want to make oscilloscope measurements, buy a real commercial
scope. I prefer analog for a first scope.

Find a local ham and put out the word you want a scope.
Most of us have more scopes than we can ever use.
Maybe you can borrow one 'till you figger out what you need.

Geography matters, but put a request for a scope on Craigslist or
equivalent.

You have a LOT more options if you are experienced, already have
a scope you can use to fix a busted new scope etc.
If you're a novice, go get a 30-40 year old analog scope CHEAP.

Lot of good info there, thanks. I have a 10mhz leader single trace scope
that worked fine last time I tried it.

Drag it out and use it. You'll quickly learn what features you need.

Do you have any recommendations on a

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used repairable scope?
Already done that TEK 465, 7704 and relatives.

The 7704 is handy 'cause you can get plugins for logic analysis,
spectrum analysis, TDR, curve tracer etc.
I've seen some recommend the Techtronics 465, since

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a lot of what I plan to use it on is digital signals/communication, I
thought storage would almost be necessary.

You need to say a LOT more about what you mean by digital
signals/communication.
RS-232 is communication and well within the capability of your leader.
Demodulating Cellphone signals is quite another matter.

An oscilloscope is a poor substitute for good design judgment.
It's a time domain instrument that is very good at looking at
individual transients. You want to know the risetime, amplitude
and "cleanliness" of signals. An oscilloscope with a delay line
will let you do that, as long as it has sufficient bandwidth for the
risetimes you're observing. Two channels will let you see relationships
between two signals. As long as you stay away from the maximum speed
stuff will run, you'll have few problems that need high resolution timing.

Once you get beyond that, it becomes complicated real fast.
Just probing the system is a nightmare.
Your problem is triggering on the desired event. You quickly get into
logic analyzer types of triggering and display. A two-channel scope
is better than one. 4 is better, but still not too helpful if you
need to trigger on 8 or 64. I once got so frustrated that I built a fixture
with a PAL on it. Reprogrammed the PAL for each complex trigger
and used that as one channel into a logic analyzer.

Digital storage has some benefits.
Lets you see what happened to signals WAY before the trigger event.
But you still have to come up with some way to trigger on the symptom.

Lets you see signals WAY to slow to be visible on an analog scope.
I futzed around with a battery tab spot welder for years. About
10 minutes after I got my first digital storage scope, it was
working a LOT better. I could see what was happening.

Post processing can come in handy. It's kinda nice to set a square
wave to exactly 50% by punching the FFT button and nulling odd harmonics.

But digital storage has lots of issues with aliased displays,
triggering, single shot sampling rate, display update rate...the
list is endless. If you know what to expect, you can deal with it.
But I still get confused sometimes.

What you need depends on whether you're debugging your own design.
I use PIC processors for most of my hobby stuff. I don't run them
faster than they're designed to go. I fix problems by inspecting
the code and using "print statements". If needed, I can use a pin
to generate a scope trigger exactly where I want to look. I rarely
use more than two scope channels.

If you're reverse-engineering or repairing someone else's stuff,
you may need a LOT more capability.

For most of my stuff, I use a TEK 308 logic analyzer. It decodes
RS-232 and GPIB. It generates word triggers into a TEK TDS540
digital scope. It's OVERKILL for most things.

You can do a lot of stuff with a cheap analog scope.
Complex stuff needs $60K equipment.
There ain't much in between. Might as well go cheap
and suffer the consequences of not being able to do some stuff.
Patience pays off when you're looking for equipment.
My TDS540 was free...the 308 was $5...plus about $10 in parts
and a week to get it all working...but that's not the norm.
Fixing undocumented stuff is not for the faint of heart.

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RogerN