Why are oscilloscopes so big?

[Maker]

I don't need an oscilloscope, I just want one to look at various waveforms, capacitors discharging, and other things that make wavy lines. I'd always thought they're really expensive (Because they are) but I've seen they go fairly cheap on eBay so I've been looking at getting one second hand.

I just don't see why they're so big. I know ones with CRT's are going to be big and heavy because there's a big heavy CRT in it but digital ones aren't any smaller*, why is this?

*I mean proper ones, not the ones on a single PCB or the "Pocket DSO" which I assume are crap.

PS; I was 7 when I first heard of them and I've wanted one ever since but I've never had any use for one till now. Yeah, I was a weird child. Well, "was" implies I'm normal now.

 

[Spark plug]

http://www.fluke.com/fluke/uken/products/scopemeters

 

[AndyStobbs]

Buy a pico

 

[julianf]

I have one of these -

its slow (20k) and ancient, but if you just want one for novelty, you could do worse.

I have no idea what they go for, but i would imagine pocket change (mine was given to me)

 

[sparkysy]

I'm sure maplins used to do a small one it was about £150 or so that was quite usefull, I will have a look!

 

[Maker]

Good luck finding a decent, reliable and small oscilloscope for anything near "cheap".

I'm sure it'll get bid up or bought now but this one looks decent (Probably well over the top for my use), and within driving distance of me. Or this one, looks much more simple.
Nearly everything here looks good to me.

Buy a pico

What's that then?

I have one of these -

its slow (20k) and ancient, but if you just want one for novelty, you could do worse.

I have no idea what they go for, but i would imagine pocket change (mine was given to me)

That looks like it would do me. What is meant by the speed?

 

[bill_gj]

Look at the Hantek scopes on eBay. You need a laptop too though.

 

[Rig Pig]

Here's a nice little modern one

 

[Maker]

Look at the Hantek scopes on eBay. You need a laptop too though.

Are they any good? It seems like the most practical solution.

 

[julianf]

That looks like it would do me. What is meant by the speed?

Frequency.

If you want to be troubleshooting modern, high speed, digital stuff, you would need something much more comprehensive.

But if youre doing no greater than 4000 series cmos / audio stuff / etc. then it would be fine

 

[Maker]

Here's a nice little modern one

View attachment 68140

That is awesomeI could watch that for hours.

 

[the snooper]

look here cheap small build it yourself

 

[Maker]

Why not just use your phone as an oscilloscope if it's 'just' for playing?

How do I do that? It is just for playing but so are all my tools really so I would like it to be half decent.

 

[Maker]

look here cheap small build it yourself

Ooh, nice, I might end up with that but I'm a bit reluctant to buy cheap far east electronics.

Whack on an app (free for android, £13,000,000,000 for fruityphones) make a lead to plug in your headphone jack (apparently), amuse yourself with squiggles for an hour. Job done.

I'd rather not risk my phone if I inadvertently connect it up wrong, it doesn't sound like there's much in the way of phone protection here.

Has anyone used a Hantek one?

 

[AdrianH]

Have a HP unit 4 trace 100MHz unit in a HP182 case, capable of seeing waveforms up to 150 MHz, lots of Knobs, magic machine, but only used on rare occasions.

Yes they are heavy, transformer for HT as well as all the discrete components in them must be a bit of weight, then there is the chassis tube etc. decent size screen is a must the smaller ones always remind me of trying to watch TV on a small 2" screen.

Cheers

Adrian

 

[AndyStobbs]

Picoscopes are digital lab (or automotive) scopes that you connect to a laptop. Loads of the older models go cheap, the Auto ones are too slow for a lot of mains based tasks.

But if its just for messing about with 12v circuits, an auto one woild be good.

 

[daleyd]

Ooh, nice, I might end up with that but I'm a bit reluctant to buy cheap far east electronics.

Buy some expensive far east ones then, they'll probably come from the same factory!!

 

[awemawson]

I made my first oscilloscope when I was about 15 in 1964. Used an ex government surplus VCR97 6" radar tube, and I drove the metalwork master at school mad helping me make up a chassis and front panel. It was fairly rudimentary using EF50 RF pentodes as the X amplifier, and a neon tube sawtooth generator as the timebase.

Had various commercial ones since then and wouldn't be without one, although it only gets used ocassionally

 

[Gas mark 5]

If it's purely for fun, how about butchering an old CRT monitor? The electron gun fires a narrow beam creating a dot on the screen, and a brace of magnets stretches it out horizontally and vertically producing an image. If you leave one set of magnets connected, stretching the dot into a line, you can send your signal to the other set, giving you a trace on the screen.

I made one years ago, initially I just used a PC speaker amplifier circuit, but after building some proper circuitry to control it, calibrating it with some known signals and drawing some scales on the screen it was vaguely usable. Not fast though, I think about 20kHz was about the most you could hope to distinguish.

If you actually want to get useful measurements though, as previously mentioned something that plugs into your computer is probably the most effective without costing the earth.

 

[julianf]

Really, £20 will get you an old scope off eBay.

For that sort of money, you may as well just buy one of those - if nothing more, itll be a cheap way to learn what you do and do not need before you spend any more (money OR time)

...and, when youre done with it, its still £20 (less fees) when you stick it back on eBay!