RE: Velleman HPS10 Hand held digital scope?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Steve Conner" <steve.conner@xxxxxxxxxxx>

hey Terry, all,

I looked up the Velleman HPS10, Maplin here in the UK have it for ? 80 which
is a lot cheaper than any other digital scope but still not what I'd call
expendable. Having said that, Velleman are a small company so I expect they
made it with off-the-shelf parts and it will be easy to get replacement
chips if (when) the front end gets fried.

http://www.maplin.co.uk/Media/PDFs/RS82_N10AQ%20Manual.pdf

I looked at the manual and it seems to have only the most basic
spit'n'sawdust features. There is no data download to a PC which is
disappointing.

The HPS10 has a 10MHz sampling rate and a 2MHz analog bandwidth. So the rise
time will be about 0.4/bw which is 200ns. Therefore I wouldn't expect it to
give an accurate picture of H-bridge switching waveforms, as Terry has shown
waveforms with rise times in the 10s of ns and nasty 25MHz ringing. This
scope would miss all that. But it would probably be plenty good enough for
most things and of course the storage is a huge bonus.

It is only single trace (there isn't a separate trigger input either) which
is a pain for that very important function of checking the voltage and
current in your DRSSTC primary are in phase. I guess you could still do this
as the switching transients tend to "splash" onto the current waveform so
you can see them.

Velleman also make a cheaper HPS5 and a more expensive HPS40. I saw this one
on sale for ? 300 which is getting towards the price of a second hand Tek
TDS220.

An even more unusual option is the GBDSO cartridge which turns a Game Boy
into a dual trace storage scope. I don't know if the kit is on sale any
more.

http://www.semis.demon.co.uk/Gameboy/DsoDemo/DsoDemo.htm

Steve C.