Help buying testing Equipment

I seem to be reaching the limit of what my poor multimeter can handle and am now looking for better testing equipment.

I think I am getting to a point where I really need an oscilloscope. I’ve been looking at digital oscilloscope from NKC:
http://www.nkcelectronics.com/digital-storage-oscilloscope-very-low-cost.html

Also, I am thinking about getting a logic analyzer. There are two that have got my eye:
Zeroplus LAP: http://www.nkcelectronics.com/zeroplus-lap16032u-logic-ana16032.html
Saleae Log Tech: http://www.saleae.com/logic/

Do these all look like good buys? Also, which of teh two logic analyzers would you buy?

I am open to other options as well. However, my budget for both is around 250 dollars.

As far as logic probes go I have to say that the Zeroplus looks a bit better to me. My reasons are thus:

  1. It’s cheaper by $30
  2. It handles ± 30V while the Saleae only supports 0-5V input. This is important if you plan to directly probe RS232 signals. They are usually ±15V.

That having been said, I have not used either one. The saleae looks smaller so if that’s your thing it’s a plus.

The saleae has half the number of inputs. But, it seems to decode more signal types. It also has nicer probes. I guess it really is a toss up… They both look reasonably nice and both have their ups and downs.

I would go for the scope and hold off on the logic analyser. These are quite messy to set up and you are not likely to get value for money out of it. I have had both and hardly ever use the analyser where as the scope is on all the time.

I spent a lot of time building an anlaog synth. Halfway through the project i bought a second hand scope. It was like i had been given an extra pair of eyes and ears. Without doubt the best money i spend on equipment, except those spend on a good soldering station.

Check this scope out: http://www.parallax.com/Store/Microcontrollers/BASICStampProgrammingKits/tabid/136/ProductID/46/List/1/Default.aspx?SortField=ProductName,ProductName

Is it better than the one I listed earlier? The specs aren’t as good.

is the analyzer really that useless? I want to be able to decode IR signals. I also often take apart electronics and try to hack addons together. I thought an analyzer would help me see what the ICs are doing better. Can all this be done on a scope?

is the analyzer really that useless? I want to be able to decode IR signals. I also often take apart electronics and try to hack addons together. I thought an analyzer would help me see what the ICs are doing better. Can all this be done on a scope?

I don’t think that logic probes are useless but it really depends on what you need to do. A logic probe is great if you know what you are doing and you have a proper decoder for the signal. Then you can really dial down and figure out whats going on. But it’s essentially a very specialized oscilloscope. (Some scopes do both) Non storage scopes can sometimes be frustrating as signals just shoot by and sometimes it’s hard to get a good static picture of what just happened. Storage scopes are nice because you can set them to trigger, record a bit, then scan over the stored data and see exactly what happened. An oscilloscope is a lot more versatile than a straight logic probe. Since an oscilloscope has 1001 uses it’s really the best bet to get first. Then if you’ve got some money and you really do want to decode signals it might be interesting to get a logic probe.

One thing about oscilloscopes: You do get what you pay for. The ones you have been linking to are very low bandwidth. That’s OK if all you are doing is looking at RS232 serial or IR signaling. It’s not as OK if you really need to capture really fast signals or transients.

I thought an analyzer would help me see what the ICs are doing better.

No a logic analiser is designed to look at a lot of signals at the same time. For example to look at all the lines on the data bus and address bus and control bus of a computer system. Then display them as a sequence of address locations and bus contents and sometimes even decode the machine code coming over the bus and display the mnemonics. It is a real pain wiring up the 32 to 64 lines into it and it can take half a day to do.

What you want is a multi channel digital storage oscilloscope to allow you see what is happening with things like I2C buses or IR signals. Most of the time you will only use two channels but sometimes you will need four. It is rare you need more and if that happens you can usually work round it.
So look for bandwidth and storage depth.

What bandwidth should I be looking for then? The Parallax scope has 200KHz and the NKC scope has 1MHz bandwidth. However, you can’t store values with the NKC scope.

What bandwidth should I be looking for then

I would have said at least 30MHz, but that seems to rule out your candidates. :frowning:

Looking for inexpensive digital oscilloscopes, …

I see “Owon” and “Extech” providing suspiciously-similar products… not sure which one is really making them and which one is just reselling them. We’re talking in the US$350 range for a new unit. http://www.drillspot.com/products/445005/Extech_381295A_Portable_Digital_Oscilloscope

I also hear “Rigol” here a lot. They seem to start at about US$600. http://www.amazon.com/Rigol-DS1052E-50MHz-Digital-Oscilloscope/dp/B001P63VOA

I just bought an Instek 1022 scope. Wonderful device given its price :
http://www.tequipment.net/InstekGDS-1022.html
2 channel (plus 1 trigger channel) digital storage, 25 MHz, lots of measurement options (Vmax/min/pp, pulse width, rise/fall time, freq…). $360 shipped- which is a lot more than you seem to want to spend but I have seen this scope compared to Tektronix ones costing 4 times as much.

The Saleae Logic analyzer looks very nice, but in the end a scope is more versatile. Having the analyzer it will be easy to figure out what I2C or SPI commands are being sent on the bus. However, that is assuming the signals are of decent quality to begin with. With a scope you can make sure the signal quality is good AND decipher the bits. However, the latter is a lot more time consuming without an analyzer.