Portable Oscilloscope

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?

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?

"Bret Cahill" <BretCahill_at_peoplepc.com> wrote in message
news:4da51516-38bf-4f45-8294-17616508874d_at_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.

Tom Biasi wrote:
"Bret Cahill" <BretCahill_at_peoplepc.com> wrote in message
news:4da51516-38bf-4f45-8294-17616508874d_at_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

"Joerg" <invalid_at_invalid.invalid> wrote in message
news:8b94lpFhsbU1_at_mid.individual.net...
Tom Biasi wrote:
"Bret Cahill" <BretCahill_at_peoplepc.com> wrote in message
news:4da51516-38bf-4f45-8294-17616508874d_at_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.

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?

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.

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.

Tom Biasi wrote:
"Joerg" <invalid_at_invalid.invalid> wrote in message
news:8b94lpFhsbU1_at_mid.individual.net...
Tom Biasi wrote:
"Bret Cahill" <BretCahill_at_peoplepc.com> wrote in message
news:4da51516-38bf-4f45-8294-17616508874d_at_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"?

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?"