On Wed, 21 Apr 2021 23:25:23 +0000, Computer Nerd Kev wrote:

> Of course at this point you've got a significant amount of front-end
> circuitry for your "simple" sound card oscilloscope. For a data logging
> application that might be quite reasonable, but for basic
> troubleshooting maybe it would be easier to just buy an old CRO (Cathode
> Ray Oscilloscope), which has the added benefit of working outside the
> audio frequency range.
>
There are some decent dual channel, 20MHz oscilloscopes appearing on eBay
and at pretty reasonable prices too. Find one locally if possible to same
freight costs: a good older 'scope is both heavy and bulky.

Also, its worth noting that a 'scope can also be used as a logic probe: a
straight high line is a stable '1', a straight low line is a stable '0'
and either a pair of lines or a square wave, depending on scope scan
speed vs signal frequency, indicates a digital signal.

Mine is a dual beam 20MHz Hameg I've had since the mid '80s and used for
everything from trouble-shooting a floppy drive interface I built for a
6809 system to checking the state of 50mAH NiCd batteries (they were used
in a timer to pulse a solenoid with a 500mA, 15mS pulse: the shape, depth
and width of the of the battery's voltage drop when the solenoid was
operated was an excellent indication of battery condition. As it aged the
voltage drop changed progressively from a 15mS wide drop with a flat
bottom and instant recovery to a deeper, wider shape with no flat bottom
and a longer recovery slope. When the flat bottom was gone it was time to
replace the NiCds.


--
Martin    | martin at
Gregorie  | gregorie dot org

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