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Community => Bar Sport => Topic started by: simon1974 on Jan 19, 2016, 11:54 pm

Title: Oscilloscope or logic analyzer
Post by: simon1974 on Jan 19, 2016, 11:54 pm
I was going to buy this --Handheld DSO203 ARM  Digital Oscilloscope 4 CH..
After reading some posts on this forum. I need some help. Some people have posted that a logic analyzer is more useful.
I'm  just a newby to hobby electronics and would be using it to explore low voltage circuits and expand my knowledge.
 
A quick ebay search has revealed lots of usb logic analyzers under £50  but I'm not sure about plugging something like this into my i7 laptop.

Can someone please show me  the light.
Thanks Simon
Title: Re: Oscilloscope or logic analyzer
Post by: simon1974 on Jan 20, 2016, 12:20 am
http://pages.ebay.com/link/?nav=item.view&id=300914430820&alt=web
 
This one!
http://pages.ebay.com/link/?nav=item.view&id=300914430820&alt=web
Title: Re: Oscilloscope or logic analyzer
Post by: dally on Jan 20, 2016, 12:29 am
usb logic analyzers under £50
a good LA is useful when you have to develop digital things, especially fpga
chipscope (as they are called in fpga world) cost thousand euro (in licenses)
while a good physical LA costs no less than 200 euro

everything else is money trashed

my suggestion is: buy a good DSO with 2 Ch, 100Mhz (say RIGOL is good)
and forget LA until you have to develop serious things

p.s.
if you just need to analyze serial wires (e.g. SPI, i2c, uart), you can buy a DSO that has "protocol" support
Rigol has these DSO, they cost no less than 500-600 euro

second hand (say 40..50% discount) can be a good alternative
Title: Re: Oscilloscope or logic analyzer
Post by: simon1974 on Jan 20, 2016, 12:36 am
Thanks +dally
Title: Re: Oscilloscope or logic analyzer
Post by: Boardburner2 on Jan 20, 2016, 12:37 am
I would agree with the oscilloscope choice.

Its possible to get e really useful used one for about 50 on ebay.

They tend to be older heavier ones so collection is really needed so that you can check operation and not pay big carriage.

I have a 50 Mhz techtronics which has served me well for 25 years.
I purchased one off ebay for 50 + post purely to replace the tube.  
Title: Re: Oscilloscope or logic analyzer
Post by: Boardburner2 on Jan 20, 2016, 12:49 am
I was going to buy this --Handheld DSO203 ARM  Digital Oscilloscope 4 CH..

While cheap the spec says that it has a band width of 8 MHZ.

That's too low imho for digital work with arduino.

While a dro is more useful, getting something better second hand will give you experience in what to look for in a scope.
Title: Re: Oscilloscope or logic analyzer
Post by: larryd on Jan 20, 2016, 12:59 am
IMO

Priority:
-Good voltmeter
-Logic probe (resistor and led will do)
-Oscilloscope DSO 2 channel, 4 if you can afford it. 100 minimum, better 250MHz Rigol
-Logic analyzer 150Mhz+ 8 or 16 channel. Saleae

.
Title: Re: Oscilloscope or logic analyzer
Post by: Boardburner2 on Jan 20, 2016, 01:04 am
You missed the temperature controlled soldering iron  :)
Good voltmeter £5 these days .
In my day they were £120 (AVO) and that was 30 yrs ago. :o
Title: Re: Oscilloscope or logic analyzer
Post by: Robin2 on Jan 20, 2016, 11:48 am
There is a looong discussion in this Thread (http://forum.arduino.cc/index.php?topic=215441.0).

I bought a DS203 and I am very happy with it. I only use it very occasionally and paying more would have made no sense. Also it is small and takes up little space when I am not using it.

I think there is a lot of value in having a device that can work independently of any PC.

...R
Title: Re: Oscilloscope or logic analyzer
Post by: dally on Jan 20, 2016, 12:12 pm
Good voltmeter £5 these days .
oh, man ...
Title: Re: Oscilloscope or logic analyzer
Post by: Boardburner2 on Jan 20, 2016, 01:46 pm
Its all relative

Avo was considered top of the range and a £5 from wall mart exceeds those specs these days.

Key is input impedance and even wall mart are 10 M OHM.

Spending more will get more bells and whistles, and a bit more accuracy but not much.

If you are on a budget better to spend on a decent iron IMHO.
Title: Re: Oscilloscope or logic analyzer
Post by: dally on Jan 20, 2016, 03:48 pm
Its all relative
of course, it's relative to your purpose
say it's OK if you need a meter to check if your car battery is around 12 Volt

Title: Re: Oscilloscope or logic analyzer
Post by: simon1974 on Jan 20, 2016, 07:43 pm
Thanks everyone. I'm  still no closer to getting my  money out yet.
I've been looking at rigol 100mhz  and hantek 100mhz 
Modes under £200-GBP and considering that I was only looking at spending half that. Has made me think very hard. So I'm starting to think that the money would probably be better spent at my local college.
I can save up for a really good oscilloscope and keep an eye out for a good deal.

Title: Re: Oscilloscope or logic analyzer
Post by: larryd on Jan 20, 2016, 09:58 pm
Unless you are going to do a lot of work in electronics, just use a logic probe (led with 220R resistor and maybe one that has a pulse stretcher)
http://www.sentex.ca/~mec1995/circ/probe1.htm (http://www.sentex.ca/~mec1995/circ/probe1.htm)

(http://www.sentex.ca/~mec1995/circ/probe1.gif)
Title: Re: Oscilloscope or logic analyzer
Post by: simon1974 on Jan 21, 2016, 12:56 am
Thanks LarryD I'll build one of those no matter what. I diside to do.  Im more into making things and circuit bending at the moment hence wanting a cheep oscilloscope!!!;-)
Title: Re: Oscilloscope or logic analyzer
Post by: keeper63 on Jan 29, 2016, 07:00 am
If you're into circuit bending (audio) - then a scope is likely to be a better thing to get than a logic analyzer - and you really don't need anything fancy. Any of the low-cost 2 channel digital o-scopes will serve you just fine, because you are dealing with audio frequencies mainly, and you only need something with 2-4 times the bandwidth of the fastest signals you are dealing with (in this case, audio - so 20 KHz or so - thus any scope with over 80 KHz bandwidth will work just fine - even one from the 1960s).

Another item you might look into is a signal generator - something that can output sine waves and square waves minimum, in the audio frequency range. There are plenty of low-cost possibilities out there (from small and cheap open-frame boards from Chinese suppliers, to homebrew 555 contraptions, to well made - but still low cost - lab bench style). Another thing that will be useful is a dual-output, fully adjustable power supply (something around 0-15 volts or so, 2-5 amps). This won't be really cheap - but it will be well worth it. You want it adjustable so that if you are unsure about current or voltage needs, you can dial in something low, and if too much is drawn, it will kick off quickly - maybe enough to save the circuit (not always, though - but faster than a fuse).

If you need to probe digital stuff, then a logic probe is likely all you'll want or need for most things you'll come across in bending. A homebrew one can be instructional, but commercial ones are readily available at a fairly low cost. Some digital multimeters even have the capability to act as such a probe (and can even tell you the frequency a signal is pulsing at, if that matters).