Portable Oscilloscope
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From: Joerg on 28 Jul 2010 10:50 Tom Biasi wrote: > "Joerg" <invalid(a)invalid.invalid> wrote in message > news:8b94lpFhsbU1(a)mid.individual.net... >> Tom Biasi wrote: >>> "Bret Cahill" <BretCahill(a)peoplepc.com> wrote in message >>> news:4da51516-38bf-4f45-8294-17616508874d(a)h40g2000pro.googlegroups.com... >>>> The markings on the housing of the 120 / 240 v ac Protek P-3502C don't >>>> say anything about power consumption, only to use a 1 amp fuse. The >>>> web page claims the newer models at least are low power or energy >>>> efficient so I hooked it up to an $8.00, 60 watt inverter on a 12 v 22 >>>> amp hr lead acid gel cell. >>>> >>>> It only drew 1.5 amps from the battery but the trace looked blurry and >>>> couldn't be adjusted. I hooked up another gel cell in parallel but >>>> the current and trace didn't change a bit. I then plugged it back >>>> into 120 ac and the trace was back in focus. >>>> >>>> Do oscilloscopes require a special sine wave inverter? >>> Seems the brightness needs to be turned all the way down when on the >>> inverter. >>> >>> >>> Bret Cahill >>> >>> The output of that inverter is far from adequate for electronics >>> equipment. >>> >> Not necessarily. I have used "power supplies from hell" when I had no >> choice. Older CRT oscilloscopes have a regular transformer-based power >> supply and they often aren't very happy with the "modified sine wave" >> from cheap converters. Tube voltages may be lower and you can't get >> proper focus, and there is always a risk something goes ... *PHUT*. But >> I never had it happen, just a little sub-par performance. >> >> The same goes for fan motors. When the power fails and I use an inverter >> for our stove fans I have to crank the speed control much higher. >> >> -- >> Regards, Joerg >> > OK so you partially disagree that the inverter is inadaquate then go on to > tell me how your use was less than satifactory. > My use of inverters with modified sine was sufficiently satisfactory. It made the equipment work, not perfectly but well enough, got the job done. What more could one want? Being a bit facetious: If one were to arrive at a distant location for a repair only to find out that there's Philips screws but only a flat blade screwdriver in the tool box, would you recommend returning to base and saying "I couldn't do it because I had the wrong tool"? -- SCNR, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Tom Biasi on 28 Jul 2010 17:43 > > Being a bit facetious: If one were to arrive at a distant location for a > repair only to find out that there's Philips screws but only a flat > blade screwdriver in the tool box, would you recommend returning to base > and saying "I couldn't do it because I had the wrong tool"? > > -- > SCNR, Joerg > Point taken, but do you realize that tool would be inadequate for the job? I guess it depends on how you define adequate and under what conditions. In a general sense one could say a straight screwdriver is inadequate for Phillips screws. Best regards, Tom
From: krw on 28 Jul 2010 18:49 On Wed, 28 Jul 2010 17:43:29 -0400, "Tom Biasi" <tombiasi(a)optonline.net> wrote: > > >> >> Being a bit facetious: If one were to arrive at a distant location for a >> repair only to find out that there's Philips screws but only a flat >> blade screwdriver in the tool box, would you recommend returning to base >> and saying "I couldn't do it because I had the wrong tool"? >> >> -- >> SCNR, Joerg >> >Point taken, but do you realize that tool would be inadequate for the job? >I guess it depends on how you define adequate and under what conditions. >In a general sense one could say a straight screwdriver is inadequate for >Phillips screws. But at some point you have to accept that you set out to drain the swamp.
From: Joerg on 28 Jul 2010 19:03 Tom Biasi wrote: >> Being a bit facetious: If one were to arrive at a distant location for a >> repair only to find out that there's Philips screws but only a flat >> blade screwdriver in the tool box, would you recommend returning to base >> and saying "I couldn't do it because I had the wrong tool"? >> >> -- >> SCNR, Joerg >> > Point taken, but do you realize that tool would be inadequate for the job? Hard to say from a distance. If Bret was able to get his measurements done and the scope did not let off a puff of smoke my vote would go to "tool was adequate enough" :-) > I guess it depends on how you define adequate and under what conditions. > In a general sense one could say a straight screwdriver is inadequate for > Phillips screws. > I'd jam it in at an angle and try to get the screw to budge. Of course, my father (metallurgy engineer by degree) always pestered me "You electrical guys, you always have to approach every bolt with an adjustable pipe wrench, do ya?" -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Michael A. Terrell on 28 Jul 2010 23:00
Joerg wrote: > > Tom Biasi wrote: > > "Joerg" <invalid(a)invalid.invalid> wrote in message > > news:8b94lpFhsbU1(a)mid.individual.net... > >> Tom Biasi wrote: > >>> "Bret Cahill" <BretCahill(a)peoplepc.com> wrote in message > >>> news:4da51516-38bf-4f45-8294-17616508874d(a)h40g2000pro.googlegroups.com... > >>>> The markings on the housing of the 120 / 240 v ac Protek P-3502C don't > >>>> say anything about power consumption, only to use a 1 amp fuse. The > >>>> web page claims the newer models at least are low power or energy > >>>> efficient so I hooked it up to an $8.00, 60 watt inverter on a 12 v 22 > >>>> amp hr lead acid gel cell. > >>>> > >>>> It only drew 1.5 amps from the battery but the trace looked blurry and > >>>> couldn't be adjusted. I hooked up another gel cell in parallel but > >>>> the current and trace didn't change a bit. I then plugged it back > >>>> into 120 ac and the trace was back in focus. > >>>> > >>>> Do oscilloscopes require a special sine wave inverter? > >>> Seems the brightness needs to be turned all the way down when on the > >>> inverter. > >>> > >>> > >>> Bret Cahill > >>> > >>> The output of that inverter is far from adequate for electronics > >>> equipment. > >>> > >> Not necessarily. I have used "power supplies from hell" when I had no > >> choice. Older CRT oscilloscopes have a regular transformer-based power > >> supply and they often aren't very happy with the "modified sine wave" > >> from cheap converters. Tube voltages may be lower and you can't get > >> proper focus, and there is always a risk something goes ... *PHUT*. But > >> I never had it happen, just a little sub-par performance. > >> > >> The same goes for fan motors. When the power fails and I use an inverter > >> for our stove fans I have to crank the speed control much higher. > >> > >> -- > >> Regards, Joerg > >> > > OK so you partially disagree that the inverter is inadaquate then go on to > > tell me how your use was less than satifactory. > > > > My use of inverters with modified sine was sufficiently satisfactory. It > made the equipment work, not perfectly but well enough, got the job > done. What more could one want? > > Being a bit facetious: If one were to arrive at a distant location for a > repair only to find out that there's Philips screws but only a flat > blade screwdriver in the tool box, would you recommend returning to base > and saying "I couldn't do it because I had the wrong tool"? And then quit because you're incompetent. :( |