Why are oscilloscopes so big?

[Maker]

Just to be clear, when you say 20khz, that's 400 times faster than mains frequency? Because that's honestly what I've been playing with (not directly from the wall, with a couple of transformers, I think it's about 30 mA)

 

[PTvor]

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.

They aren't and weren't always "big"

http://www.thevalvepage.com/testeq/cossor/1039m/1039m.htm


But that thing's limited and was produced for TV techs to be able to see a wave form and tune to a null point, or produce as near to the waveform in the book as they could with twiddling.

But if you wanted more features and more bandwidth, as well as a tube which could do it justice and the EHT supply to feed it, plus a front panel to accommodate all the controls and especially with valves, you were talking some size, especially with a transformer to generate the EHT directly from the mains, that's before the days of solid state rectifiers.

Best value in scopes is s/h Topward/LG/Hameg/etc 20MHz scopes for £30-40 which are fairly reliable and good enough for most things, certainly for investigating multivibrators and so on. Valve scopes require dedication. Top end vintage Tekronix and HP scopes require serious dedication, My go to scope is a 20MHz Topward, anything beyond it, a Tek 475 or HP 1744 storage scope. I'm on the lookout for reasonably priced scrappers to keep the Tek and HP going. Apart from that I think I have a dozen valve scopes, most of which work.

 

[500e]

The Hameg 203 on the bay for £20 will cover most of what you want have had one for years does most of what we use them for we also have a DF4000 if we want higher BW & functionality

 

[voipio]

These aren't too large or heavy:

http://cpc.farnell.com/tenma/72-10510/oscilloscope-dso-2ch-25mhz/dp/IN06875?MER=e-bb45-00001001

 

[the snooper]

These aren't too large or heavy:

http://cpc.farnell.com/tenma/72-10510/oscilloscope-dso-2ch-25mhz/dp/IN06875?MER=e-bb45-00001001

he will find the price too heavy

 

[500e]

http://www.thevalvepage.com/testeq/cossor/1039m/1039m.htm

That is a blast from the past I was an apprentice TV service tech in the late 50s early 60s
We have a knock about unit in one of the vans it is an Owon can be battery powered

• 

Owon PDS5022T Portable Digital Storage Oscilloscope and Digital Multimeter, 8" Color TFT LCD, 2 Channels, 25MHz, 100MS/s Real

 

[Harry_Worth]

That Owon looks small and neat - one on ebay with box for just £199.00. A complete bargain when compared to what a scope would have cost when I first got into the game in 1980. It also appears considerably smaller! If that's still too rich I've an old Tektronix 2235 I bought from Stewarts of Reading (think they're still going) for £400.00 back in 1995 or thereabouts. If you're ever in my area it's available for a beer (I'll check to see if it's survived my damp garage first to make sure it's worth a beer). Can't see a CRT scope is really worth anything as digital scopes are so cheap!

 

[Maker]

If that's still too rich I've an old Tektronix 2235 I bought from Stewarts of Reading (think they're still going) for £400.00 back in 1995 or thereabouts. If you're ever in my area it's available for a beer (I'll check to see if it's survived my damp garage first to make sure it's worth a beer). Can't see a CRT scope is really worth anything as digital scopes are so cheap!

Thanks for the offer, I might just take you up on that. What is your area?

 

[ajlelectronics]

I have a Farnell 20MHz dual beam in my workshop that is rarely used. I could sell that I suppose. Not sure of its value though.

 

[Harry_Worth]

Thanks for the offer, I might just take you up on that. What is your area?

Southampton