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Scorpio · Posted: Sun Sep 26, 2010 9:45 pm Post subject: Oscilloscope

Anyone know anything about purchasing a good digital oscilloscope ? Looking originally to us use it to graph small dynamo voltage output as a function of rpm but also want to future proof for other possible applications. Screen or no screen (ie plug to laptop) either is fine think I want two channel minimum with very easy to use functions / software anyone have any advice or experience?
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

rat · Posted: Sun Sep 26, 2010 10:15 pm Post subject:

We have a picoscope 2203 at work. For the price it seesms a good bit of kit. The techtronics and hameg scopes we have are much faster with the odd extra feature, but then they also cost about 15x-30x as much.

Might be worth a play with their software in demo mode to see if you get along with it.

http://www.picotech.com/oscilloscope-specifications.html

!tom · Posted: Tue Sep 28, 2010 1:08 pm Post subject:

You've got to first define what you need it to do, before you decide on what scope you're going to need.

Do you need a 5 MHz sampling rate?

Do you need 16 bits?

Or, are a few kHz needed?

How about impedance?

There's a huge variety of prices from the bottom end to the top end, but unless you're debugging digital circuit layout, you're likely not going to need top of the line kit.

You might want to look into this project or something similar, as it may fulfill you needs.
_________________
78 924 NA
5-lug

Mike9311 · Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish

techtronics on ebay. For 400US you can get a real decent scope
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

If that`s all you want it for you could likely get away with the signal fed into your PC sound card via a few dividing resistors, and some free download software. Then depending on speed, functions, brand the cost rises.

Future proof ... pfft

Think of Homer Simpson buying the computer that won`t get outdated.

For what Scorp? ever noticed digital speeds are increasing? Sounds like you only want to log DC with this project so a basic 20Mhz will more than suffice. All you need for any audio, auto EFI, basic RF and all but high speed digital signals. Sure you can buy a 20Ghz Tektronix that will do that job too. Did you win lotto?

Mike9311 · Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish

RC, now you reminded me with that sound card stuff

I use this when I build and test speakers I build (too many hobbies and interests + work)

http://www.trueaudio.com/rta_abt1.htm

I also used it to set my Ducati cam belts with a microphone. Strum the belt and adjust belt frequency.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

pocketscience · Posted: Thu Sep 30, 2010 8:59 pm Post subject:

Scorp I built a kit one a few months back for some 'lectronics gear I'm playing with (robots and other microcontroller gear)... it's cheap and pretty basic, but works great for my purposes... what are yours exactly?

It can take screen grabs of the traces which can then be poured down a serial link to your PC.

G.
_________________
Whoever said you can't buy happiness forgot about Porsche!
81 924 N/A, GTS lights, Saratoga, interior, headers, Integral cam, EFI (sold)
95 993
69 911

924aussie · Posted: Thu Sep 30, 2010 10:24 pm Post subject:

Gavin we come acrosss robotic arms that are used to take ice creams out of vending machines if you want some next time we get them I will keep you some.

Scorpio, give me a call during the day, I may have a scope for you at work you can borrow.

Alan
_________________
green 924 .. 1980 rego 924PSH
1998 Mopar Neon ... sick
2003 Challenger / Montery 4WD
1995 Hyundai Scoupe ... sold
1998 Nissan Silvia ... sons back from OS he has taken it
BIG BLOODY MOTORHOME 300zx Sold
1980 Fire truck Sold

pocketscience · Posted: Thu Sep 30, 2010 10:27 pm Post subject:

Scorpio · Posted: Fri Oct 01, 2010 11:20 pm Post subject:

good advice boys!...

future proof= highly doubt i see myself ever doing anything needing a 100mhz oscilliscope but who knows...

At the moment i just want something easy to use with good user interface software that can datalog nicely.

The application is my postgrad thesis project- A device that harnesses electrical energy from ocean swell. Currently working on a small prototype for the pupose of showing "Proof of concept" Outcome im after is maximum power output from the device/ power from area exposed to swell= efficiency of the device at converting wave energy into electrical energy

Using Maximum power theorem i want to
1)find maximum possible power output from two small dynamos
2) then calculate the dynamos"efficient max power" (lower then max power according to max power theorem ie short circuit power)
3) test the device and find overall efficiency- considering it works

Need ideas to provide a useful equation suitable for the device that takes the following into account
1) wave amplitude
2)wave frequency
3) dynamo max power
4) dynamo max efficient power
5) overall device efficiency and power output(as a function of wave size /frequency parameters)

Oscilliscope will give me a pretty power output picture for my small prototype

p.s anyone know a Laymans method for calculating flywheel size? (assuming solid rotational disk for moment of inertia) found a couple of methods but cant quite pinpoint what im after ie stored mechanical energy/work/power. Need the flywheel to store mechanical rotation during the fall of a wave(50% of the time) so that the dynamo doesnt stop-start
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

924aussie · Posted: Sat Oct 02, 2010 12:15 am Post subject:

I think he is saying he is going to play in the WAVE pool down the coast

I have a 100 at work

Alan
_________________
green 924 .. 1980 rego 924PSH
1998 Mopar Neon ... sick
2003 Challenger / Montery 4WD
1995 Hyundai Scoupe ... sold
1998 Nissan Silvia ... sons back from OS he has taken it
BIG BLOODY MOTORHOME 300zx Sold
1980 Fire truck Sold