[sdiy] first oscilloscope help

[harrybissell at wowway.com]

I don't think its even close to satisfying the need for
an oscilloscope...

A good oscilloscope is test equipment, it needs to be trusted
apart from the circuit to be tested... not sharing a supply. This
schematic is likely to mess up whatever it is connected to...

It does not have a high input impedance. Unless the voltage you
monitored was VERY well buffered, the 10K input would kill it.

The input will have a varying DC bias, which will also affect the circuit.

Most scopes would have at least 8 bits of vertical resolution... this one
has less than four. Ditto the horizontal resolution.

You'd need triggered sweep, I think this one would not have that (I didn't
look that close...)

My $.02 - buy a decent used scope, then build this circuit as a toy

H^) harry



On Tue, 13 Jan 2009 19:28:46 -0000, Electronic Battle wrote
> > I'm looking for my first oscilloscope, it needs to be small, cheep, any
> > suggestions,Any recommendations suggestions much appreciated
> 
> Whilst it probably won't satisfy the needs of someone starting off 
> in the world of oscilloscopes, a possible DIY solution (handy as a 
> general purpose waveform monitor) could be this circuit:
> 
> http://www.geocities.com/SiliconValley/Lakes/7156/articl3.htm
> featured in
> http://blog.makezine.com/archive/2008/06/led_oscope_schematic.html
> which refers to
> http://blog.makezine.com/archive/2007/11/video_dave_clausen_and_hi.html
> 
> I found the links because I have recently found a number of LM3914s 
> which I plan to build into some eurorack modules, one of which will 
> be an 8x8 CV matrix and another may be a small LED CRO as per the above.
> 
> Have fun!
> 
> RMC
> 
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Harry Bissell & Nora Abdullah 4eva