For the real "cheapskate" in all of us it's hard to resist a sound card scope. Basically they use the stereo ADC in a sound card to record two channels. The software is freely downloadable. Until last week I would have pointed out the caveat of a sound card's AGC (automatic gain control) and AC coupling preventing the measurement of absolute voltages (even tough it can display relative waveforms). But recently I came across a web site where they had modified the sound card to bypass those circuits. (if you're interested let me know and I'll dig up some links) But it does still have the other drawback of topping out at audio frequencies ~44Khz sampling. (still can be useful at the price) I have to agree with others, when you're ready for a "real" scope look to the used market. I picked up an Instek OS-622B 20Mhz dual trace analog for $70 USD a few months back. One thing to watch out for, if they don't include probes and manuals. I haven't been able to find a manual (if anybody has one, I'd like to here from you) , and although I recently found some less expensive probes, better probes can easily cost more than I paid for the scope. If at all possible I'd avoid anything single channel. Most of the time the interesting thing to watch is how one signal relates to another. And watch out for some of the PC based products, may of them cost nearly as much as a "real" scope (or more!) but some of them have very limited bandwidth. -Denny ----- Original Message -----=20 From: "Hulatt, Jon" To: Sent: Friday, October 31, 2003 6:17 AM Subject: [EE:] choosing a scope I've only recently got started with PIC. I'm a computer programmer by trade, and a consultancy/contract job i had recently caused me to dip my hands into pic development for a simple project- basically sampling A/D at precisely 25Hz and chucking the data out to a PC on the USART. I've got an A-Level in electronics, but my experience ends there. Safe to say i'm not a complete monkey, more of an educated baboon. Anyway, despite that project having finished, i'm still playing with pics but now on a hobbyist level. It's good fun and i'm enjoying it. There are lots of things in the pipeline for me, mainly projects for my car. But i'm coming to the realisation that I could really do with an oscilloscope. But, on my hobby budget, I can't afford to spend very much. I could possibly stretch as far as =A3200, but i'd prefer not to go past =A3150. The problem is, beyond the usage of scopes at college, I don't really know enough about what i'm going to use it for to be able to spec out what I realistically need. I've seen that I can get a new Kenwood CS1010 for =A3160, but it's bandwidth is 10MHz and it's single trace. Am I going to want more bandwidth than that for PIC related work? Then there is the option of the elektor gameboy scope, or the PICO pc-based scopes. These appeal less- i'd rather have a standalone unit. But are they going to be suitable for my usage? Are there any other options i've not considered? It's kind of a funny question really. I'm asking for some of you guys to tell me what I want, if you know what i mean!!! Thanks in advance for your comments and info. Jon -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.