Maximum Power Point Tracking: Optimizing Solar Panels 58 Comments by: Maya Posch...

[server]

Ed Lee <edward.ming.lee@gmail.com> wrote:
> But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

High voltage can destroy resistors, but this seem to be quite fast.

> The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

Lot of folks live in countries where line voltage is 230V. So 50 volts
makes a lot of difference.

> I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

I know nothing about CenTech meters. But I have several \"DT830B\"
meters. Available schematics shows 3 resistors in series for 1000V.
My oldest one have 2 resistors. Newest one have single resistor.
Standard miniature resistors are rated for 250V, one can get
better ones, but I doubt that one can get cheaply 1000V capable
ones. Still, meter is marked as 1000V DC, 700V AC (the same
as old meters).

--
Waldek Hebisch

 

[server]

Ed Lee <edward.ming.lee@gmail.com> wrote:
> But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

High voltage can destroy resistors, but this seem to be quite fast.

> The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

Lot of folks live in countries where line voltage is 230V. So 50 volts
makes a lot of difference.

> I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

I know nothing about CenTech meters. But I have several \"DT830B\"
meters. Available schematics shows 3 resistors in series for 1000V.
My oldest one have 2 resistors. Newest one have single resistor.
Standard miniature resistors are rated for 250V, one can get
better ones, but I doubt that one can get cheaply 1000V capable
ones. Still, meter is marked as 1000V DC, 700V AC (the same
as old meters).

--
Waldek Hebisch

 

[Joerg]

On 1/2/23 5:57 PM, Phil Hobbs wrote:

John Larkin wrote:
On Mon, 2 Jan 2023 11:00:52 -0800, Joerg <news@analogconsultants.com
wrote:

On 1/1/23 11:08 PM, Jan Panteltje wrote:
On a sunny day (Sun, 01 Jan 2023 20:04:49 -0800) it happened
John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
mrl4rhhtkup3sn9t4an65r9buogjtk9er1@4ax.com>:


https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp



 >>>> I\'ve been thinking for some time now that EE schools don\'t
turn out
people who like electricity, but maker culture might.


It\'s almost always been that way. Except in the last century it
was ham radio. I learned way more useful stuff that way that in
years at the university.

I think that electrical instincts should be acquired young. Then the
 college courses add the theory. That\'s why the lego/maker/Raspberry
Pi thing is interesting.


I agree.  As a young teenage hobbyist with little guidance, I went
through about four years of frustration at not being able to design my
own circuits.  I\'d salvaged all these tubes and things from a couple of
old TVs that my folks were chucking out, but didn\'t really know how they
worked.  (Transistors were too expensive, and IC prices were just moving
down from the stratosphere.)

That bottled-up frustration gave me a fire in the belly to figure it all
out, which eventually I mostly did.  (Never got round to using anything
from that Motorola MNOS nonvolatile memory book they sent me, though.)

I started building my own stuff very early on. PRoblem was, I took what
I had learned in physics class literally. Well, initially. Like that
capacitors are ideal components. Until one fine day the fluorescent
lights in my room dimmed and I new they weren\'t dimmable. What the heck?
Huh? ... *POP* .. WHOOOSH ... hisssss

That was one of the electrolytics that had turned itself into a missile
and whizzed by inches from my left eye. Whew! I learned about ESR the
hard way. It took some plaster out of the ceiling and after return to
earth melted an ugly splotch into the carpet.

At IBM, I was occasionally asked to interview candidates, and one of the
things I always asked them was whether they had any hobby background in
electronics or physical science. ...

Bingo! Exactly what I did.

... Almost all the best designers I know
started out as hobbyists, which ISTM says more about the fire in the
belly than the expertise so acquired.

Now if you\'d just get off your duff and write that \"Electronics From
Scratch\" book you used to talk about, we might have a few more.

In the EE school I was in it was known that only \'hobbyists\' would
pass the final exams. The dropout in the first year was very very
very high.


At my university the drop-out rate (start to degree) was at times 83%.

Too many kids selected an EE degree based on some high school
counselor\'s advice, or dreams of a tidy income. Too late.

I dunno.  Washing out of a hard program isn\'t the worst thing that can
happen to a young person.  It\'s not nearly as bad as hanging on by the
skin of your teeth and then failing over a decade or so in the industry.

The old saying, \"C\'s get degrees\" has caused a lot of misery of that sort.

I had pretty bad grades because I worked a lot on the side, did
\"pre-degree consulting\" and stuff like that. Bad grades are ok.

For the 30 or so in the first year, I was 1 of the 4 people at the
final graduation party in the local pub,

Granny\'s radio with 10 transistors? You mean those old radio bulbs?

Give me some and I will build you a radio or TV (if you can find an
old CRT).


In the old days that also required a crate of beer and some Ouzo

[...]

Barbaric. Rum and Coke is the ideal balance. The rum numbs your
frontal cortex and the sugar and caffeine power up the better parts.

Gin and tonic for us recovering Commonwealth types, thanks.  Lately I\'ve
been enjoying Inverroche Verdant from South Africa, with lots of ice and
a splash of Fever Tree tonic.  Highly recommended.

I am currently on a no-booze phase, to lose weight. Exercise alone ain\'t
cutting it.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 1/2/23 5:57 PM, Phil Hobbs wrote:

John Larkin wrote:
On Mon, 2 Jan 2023 11:00:52 -0800, Joerg <news@analogconsultants.com
wrote:

On 1/1/23 11:08 PM, Jan Panteltje wrote:
On a sunny day (Sun, 01 Jan 2023 20:04:49 -0800) it happened
John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
mrl4rhhtkup3sn9t4an65r9buogjtk9er1@4ax.com>:


https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp



 >>>> I\'ve been thinking for some time now that EE schools don\'t
turn out
people who like electricity, but maker culture might.


It\'s almost always been that way. Except in the last century it
was ham radio. I learned way more useful stuff that way that in
years at the university.

I think that electrical instincts should be acquired young. Then the
 college courses add the theory. That\'s why the lego/maker/Raspberry
Pi thing is interesting.


I agree.  As a young teenage hobbyist with little guidance, I went
through about four years of frustration at not being able to design my
own circuits.  I\'d salvaged all these tubes and things from a couple of
old TVs that my folks were chucking out, but didn\'t really know how they
worked.  (Transistors were too expensive, and IC prices were just moving
down from the stratosphere.)

That bottled-up frustration gave me a fire in the belly to figure it all
out, which eventually I mostly did.  (Never got round to using anything
from that Motorola MNOS nonvolatile memory book they sent me, though.)

I started building my own stuff very early on. PRoblem was, I took what
I had learned in physics class literally. Well, initially. Like that
capacitors are ideal components. Until one fine day the fluorescent
lights in my room dimmed and I new they weren\'t dimmable. What the heck?
Huh? ... *POP* .. WHOOOSH ... hisssss

That was one of the electrolytics that had turned itself into a missile
and whizzed by inches from my left eye. Whew! I learned about ESR the
hard way. It took some plaster out of the ceiling and after return to
earth melted an ugly splotch into the carpet.

At IBM, I was occasionally asked to interview candidates, and one of the
things I always asked them was whether they had any hobby background in
electronics or physical science. ...

Bingo! Exactly what I did.

... Almost all the best designers I know
started out as hobbyists, which ISTM says more about the fire in the
belly than the expertise so acquired.

Now if you\'d just get off your duff and write that \"Electronics From
Scratch\" book you used to talk about, we might have a few more.

In the EE school I was in it was known that only \'hobbyists\' would
pass the final exams. The dropout in the first year was very very
very high.


At my university the drop-out rate (start to degree) was at times 83%.

Too many kids selected an EE degree based on some high school
counselor\'s advice, or dreams of a tidy income. Too late.

I dunno.  Washing out of a hard program isn\'t the worst thing that can
happen to a young person.  It\'s not nearly as bad as hanging on by the
skin of your teeth and then failing over a decade or so in the industry.

The old saying, \"C\'s get degrees\" has caused a lot of misery of that sort.

I had pretty bad grades because I worked a lot on the side, did
\"pre-degree consulting\" and stuff like that. Bad grades are ok.

For the 30 or so in the first year, I was 1 of the 4 people at the
final graduation party in the local pub,

Granny\'s radio with 10 transistors? You mean those old radio bulbs?

Give me some and I will build you a radio or TV (if you can find an
old CRT).


In the old days that also required a crate of beer and some Ouzo

[...]

Barbaric. Rum and Coke is the ideal balance. The rum numbs your
frontal cortex and the sugar and caffeine power up the better parts.

Gin and tonic for us recovering Commonwealth types, thanks.  Lately I\'ve
been enjoying Inverroche Verdant from South Africa, with lots of ice and
a splash of Fever Tree tonic.  Highly recommended.

I am currently on a no-booze phase, to lose weight. Exercise alone ain\'t
cutting it.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 1/2/23 5:57 PM, Phil Hobbs wrote:

John Larkin wrote:
On Mon, 2 Jan 2023 11:00:52 -0800, Joerg <news@analogconsultants.com
wrote:

On 1/1/23 11:08 PM, Jan Panteltje wrote:
On a sunny day (Sun, 01 Jan 2023 20:04:49 -0800) it happened
John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
mrl4rhhtkup3sn9t4an65r9buogjtk9er1@4ax.com>:


https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp



 >>>> I\'ve been thinking for some time now that EE schools don\'t
turn out
people who like electricity, but maker culture might.


It\'s almost always been that way. Except in the last century it
was ham radio. I learned way more useful stuff that way that in
years at the university.

I think that electrical instincts should be acquired young. Then the
 college courses add the theory. That\'s why the lego/maker/Raspberry
Pi thing is interesting.


I agree.  As a young teenage hobbyist with little guidance, I went
through about four years of frustration at not being able to design my
own circuits.  I\'d salvaged all these tubes and things from a couple of
old TVs that my folks were chucking out, but didn\'t really know how they
worked.  (Transistors were too expensive, and IC prices were just moving
down from the stratosphere.)

That bottled-up frustration gave me a fire in the belly to figure it all
out, which eventually I mostly did.  (Never got round to using anything
from that Motorola MNOS nonvolatile memory book they sent me, though.)

I started building my own stuff very early on. PRoblem was, I took what
I had learned in physics class literally. Well, initially. Like that
capacitors are ideal components. Until one fine day the fluorescent
lights in my room dimmed and I new they weren\'t dimmable. What the heck?
Huh? ... *POP* .. WHOOOSH ... hisssss

That was one of the electrolytics that had turned itself into a missile
and whizzed by inches from my left eye. Whew! I learned about ESR the
hard way. It took some plaster out of the ceiling and after return to
earth melted an ugly splotch into the carpet.

At IBM, I was occasionally asked to interview candidates, and one of the
things I always asked them was whether they had any hobby background in
electronics or physical science. ...

Bingo! Exactly what I did.

... Almost all the best designers I know
started out as hobbyists, which ISTM says more about the fire in the
belly than the expertise so acquired.

Now if you\'d just get off your duff and write that \"Electronics From
Scratch\" book you used to talk about, we might have a few more.

In the EE school I was in it was known that only \'hobbyists\' would
pass the final exams. The dropout in the first year was very very
very high.


At my university the drop-out rate (start to degree) was at times 83%.

Too many kids selected an EE degree based on some high school
counselor\'s advice, or dreams of a tidy income. Too late.

I dunno.  Washing out of a hard program isn\'t the worst thing that can
happen to a young person.  It\'s not nearly as bad as hanging on by the
skin of your teeth and then failing over a decade or so in the industry.

The old saying, \"C\'s get degrees\" has caused a lot of misery of that sort.

I had pretty bad grades because I worked a lot on the side, did
\"pre-degree consulting\" and stuff like that. Bad grades are ok.

For the 30 or so in the first year, I was 1 of the 4 people at the
final graduation party in the local pub,

Granny\'s radio with 10 transistors? You mean those old radio bulbs?

Give me some and I will build you a radio or TV (if you can find an
old CRT).


In the old days that also required a crate of beer and some Ouzo

[...]

Barbaric. Rum and Coke is the ideal balance. The rum numbs your
frontal cortex and the sugar and caffeine power up the better parts.

Gin and tonic for us recovering Commonwealth types, thanks.  Lately I\'ve
been enjoying Inverroche Verdant from South Africa, with lots of ice and
a splash of Fever Tree tonic.  Highly recommended.

I am currently on a no-booze phase, to lose weight. Exercise alone ain\'t
cutting it.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Mon, 2 Jan 2023 14:35:42 -0800 (PST), \"ke...@kjwdesigns.com\"
<keith@kjwdesigns.com> wrote:

On Monday, 2 January 2023 at 07:36:21 UTC-8, John Larkin wrote:
...
You can drain your Tesla to keep the lights on, as long as you don\'t
plan to go anywhere.

This is electrical engineering. Numbers always win.

But the financial numbers for solar and wind are better than for fossil fuel.

Not when the lights are out.

Renewables are also immune to fuel price increases, that is particularly relevant for natural gas which has more than doubled in price in the last five years.

For residential solar the ROI can be 10-15% per year.

When subsidized.

So yes - the numbers do win.

kw

 

[John Larkin]

On Mon, 2 Jan 2023 14:35:42 -0800 (PST), \"ke...@kjwdesigns.com\"
<keith@kjwdesigns.com> wrote:

On Monday, 2 January 2023 at 07:36:21 UTC-8, John Larkin wrote:
...
You can drain your Tesla to keep the lights on, as long as you don\'t
plan to go anywhere.

This is electrical engineering. Numbers always win.

But the financial numbers for solar and wind are better than for fossil fuel.

Not when the lights are out.

Renewables are also immune to fuel price increases, that is particularly relevant for natural gas which has more than doubled in price in the last five years.

For residential solar the ROI can be 10-15% per year.

When subsidized.

So yes - the numbers do win.

kw

 

[John Larkin]

On Mon, 2 Jan 2023 14:35:42 -0800 (PST), \"ke...@kjwdesigns.com\"
<keith@kjwdesigns.com> wrote:

On Monday, 2 January 2023 at 07:36:21 UTC-8, John Larkin wrote:
...
You can drain your Tesla to keep the lights on, as long as you don\'t
plan to go anywhere.

This is electrical engineering. Numbers always win.

But the financial numbers for solar and wind are better than for fossil fuel.

Not when the lights are out.

Renewables are also immune to fuel price increases, that is particularly relevant for natural gas which has more than doubled in price in the last five years.

For residential solar the ROI can be 10-15% per year.

When subsidized.

So yes - the numbers do win.

kw

 

[Jasen Betts]

On 2023-01-03, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:

On Tue, 03 Jan 2023 06:17:07 GMT, Jan Panteltje
pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Mon, 2 Jan 2023 22:03:45 -0000 (UTC)) it happened Cydrome
Leader <presence@MUNGEpanix.com> wrote in <tovkc1$sj3$1@reader2.panix.com>:

Uh, pop mail has been obsolete for like 20 years now. Not sure what the
hell you\'re doing wrong, other than everything.

Well using it every day since 1998.
Have a nice directory with ALL emails since that day.
Easy to search for keywords with \'grep\'.
Checking mail with fetchmail takes a second..
Most is scripted,
Pine as email reader,
On my laptop, or any Pi I have..

And reasonable secure (never a problem since 1998).

Backups with one command (script).

If you count the number of productive hours lost
by clicking around in microsore shit then at some hourly rate you have saved
maybe zillions... using fetchmail.
Not even counting the update downloads, energy used, frustration
and no way to find anything back to 1998 in a flash.
DO YOU NOT SEE YOU ARE BING SUCKED BY microsore and others?







The Outlook webmail is sort of a good concept, but the actual product
is terrible, slow and ugly and clumsy and buggy. Why can\'t Microsoft
code?

That woulkd be more cost for less profit.

--
Jasen.
pǝsɹǝʌǝɹ sʇɥƃᴉɹ ll∀

 

[Jasen Betts]

On 2023-01-03, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:

On Tue, 03 Jan 2023 06:17:07 GMT, Jan Panteltje
pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Mon, 2 Jan 2023 22:03:45 -0000 (UTC)) it happened Cydrome
Leader <presence@MUNGEpanix.com> wrote in <tovkc1$sj3$1@reader2.panix.com>:

Uh, pop mail has been obsolete for like 20 years now. Not sure what the
hell you\'re doing wrong, other than everything.

Well using it every day since 1998.
Have a nice directory with ALL emails since that day.
Easy to search for keywords with \'grep\'.
Checking mail with fetchmail takes a second..
Most is scripted,
Pine as email reader,
On my laptop, or any Pi I have..

And reasonable secure (never a problem since 1998).

Backups with one command (script).

If you count the number of productive hours lost
by clicking around in microsore shit then at some hourly rate you have saved
maybe zillions... using fetchmail.
Not even counting the update downloads, energy used, frustration
and no way to find anything back to 1998 in a flash.
DO YOU NOT SEE YOU ARE BING SUCKED BY microsore and others?







The Outlook webmail is sort of a good concept, but the actual product
is terrible, slow and ugly and clumsy and buggy. Why can\'t Microsoft
code?

That woulkd be more cost for less profit.

--
Jasen.
pǝsɹǝʌǝɹ sʇɥƃᴉɹ ll∀

 

[Jasen Betts]

On 2023-01-03, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:

On Tue, 03 Jan 2023 06:17:07 GMT, Jan Panteltje
pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Mon, 2 Jan 2023 22:03:45 -0000 (UTC)) it happened Cydrome
Leader <presence@MUNGEpanix.com> wrote in <tovkc1$sj3$1@reader2.panix.com>:

Uh, pop mail has been obsolete for like 20 years now. Not sure what the
hell you\'re doing wrong, other than everything.

Well using it every day since 1998.
Have a nice directory with ALL emails since that day.
Easy to search for keywords with \'grep\'.
Checking mail with fetchmail takes a second..
Most is scripted,
Pine as email reader,
On my laptop, or any Pi I have..

And reasonable secure (never a problem since 1998).

Backups with one command (script).

If you count the number of productive hours lost
by clicking around in microsore shit then at some hourly rate you have saved
maybe zillions... using fetchmail.
Not even counting the update downloads, energy used, frustration
and no way to find anything back to 1998 in a flash.
DO YOU NOT SEE YOU ARE BING SUCKED BY microsore and others?







The Outlook webmail is sort of a good concept, but the actual product
is terrible, slow and ugly and clumsy and buggy. Why can\'t Microsoft
code?

That woulkd be more cost for less profit.

--
Jasen.
pǝsɹǝʌǝɹ sʇɥƃᴉɹ ll∀

 

[Dan Purgert]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

On 2023-01-06, Don Y wrote:

On 1/6/2023 11:00 AM, Don Y wrote:

They are great exemplars for showing the *cost* of different approaches
(sort is sort is sort, right?  so, wouldn\'t you opt for the cheapest??)

Cheapest is likely also the least efficient in terms of \"time\", and
nobody these days is gonna care if you took another 200 MiB of RAM to
get something done if it \"feels\" faster for the end user.

But, you might not *have* those resources (time, space, money) to \"waste\".

Speaking of resources (and a tie-in with your interest in writing ASM)...

I have to revisit my monitor to add some parameter support for my
BOOTP client. So, was thinking how good a monitor would be, for
you, to develop your ASM skills and end up with a useful tool,
in the process!

Well this conversation didn\'t just to to ludicrous speed or anything

Gonna take some noodling around since my mainstay into ASM is with AVR
micros (and as such, have a fair number of caveats that may not
necessarily appear in a PC utilizing BOOTP).

My first iteration (soon(tm)) will most likely be pseudocode, and
probably a massive list of assumptions / restrictions / etc. that lay
the groundwork for all the rest before I go digging my own grave here.

Given it\'s bound to be long, I\'ll likely post \"most\" of it to my own
website and send the link back here; rather then sending messages that
will likely span into several kilobytes.

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--
|_|O|_|
|_|_|O| Github: https://github.com/dpurgert
|O|O|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860

 

[Dan Purgert]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

On 2023-01-06, Don Y wrote:

On 1/6/2023 11:00 AM, Don Y wrote:

They are great exemplars for showing the *cost* of different approaches
(sort is sort is sort, right?  so, wouldn\'t you opt for the cheapest??)

Cheapest is likely also the least efficient in terms of \"time\", and
nobody these days is gonna care if you took another 200 MiB of RAM to
get something done if it \"feels\" faster for the end user.

But, you might not *have* those resources (time, space, money) to \"waste\".

Speaking of resources (and a tie-in with your interest in writing ASM)...

I have to revisit my monitor to add some parameter support for my
BOOTP client. So, was thinking how good a monitor would be, for
you, to develop your ASM skills and end up with a useful tool,
in the process!

Well this conversation didn\'t just to to ludicrous speed or anything

Gonna take some noodling around since my mainstay into ASM is with AVR
micros (and as such, have a fair number of caveats that may not
necessarily appear in a PC utilizing BOOTP).

My first iteration (soon(tm)) will most likely be pseudocode, and
probably a massive list of assumptions / restrictions / etc. that lay
the groundwork for all the rest before I go digging my own grave here.

Given it\'s bound to be long, I\'ll likely post \"most\" of it to my own
website and send the link back here; rather then sending messages that
will likely span into several kilobytes.

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--
|_|O|_|
|_|_|O| Github: https://github.com/dpurgert
|O|O|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860

 

[Dan Purgert]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

On 2023-01-06, Don Y wrote:

On 1/6/2023 11:00 AM, Don Y wrote:

They are great exemplars for showing the *cost* of different approaches
(sort is sort is sort, right?  so, wouldn\'t you opt for the cheapest??)

Cheapest is likely also the least efficient in terms of \"time\", and
nobody these days is gonna care if you took another 200 MiB of RAM to
get something done if it \"feels\" faster for the end user.

But, you might not *have* those resources (time, space, money) to \"waste\".

Speaking of resources (and a tie-in with your interest in writing ASM)...

I have to revisit my monitor to add some parameter support for my
BOOTP client. So, was thinking how good a monitor would be, for
you, to develop your ASM skills and end up with a useful tool,
in the process!

Well this conversation didn\'t just to to ludicrous speed or anything

Gonna take some noodling around since my mainstay into ASM is with AVR
micros (and as such, have a fair number of caveats that may not
necessarily appear in a PC utilizing BOOTP).

My first iteration (soon(tm)) will most likely be pseudocode, and
probably a massive list of assumptions / restrictions / etc. that lay
the groundwork for all the rest before I go digging my own grave here.

Given it\'s bound to be long, I\'ll likely post \"most\" of it to my own
website and send the link back here; rather then sending messages that
will likely span into several kilobytes.

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--
|_|O|_|
|_|_|O| Github: https://github.com/dpurgert
|O|O|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860

 

[Anthony William Sloman]

On Monday, January 9, 2023 at 8:33:12 AM UTC+11, Jeroen Belleman wrote:

On 2023-01-08 20:44, John Larkin wrote:
On Sun, 8 Jan 2023 19:02:15 -0000 (UTC), anti...@math.uni.wroc.pl
wrote:

John Larkin <jla...@highlandsnipmetechnology.com> wrote:
On Sat, 7 Jan 2023 01:04:32 -0000 (UTC), anti...@math.uni.wroc.pl
wrote:

Ed Lee <edward....@gmail.com> wrote:
But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

High voltage can destroy resistors, but this seem to be quite fast.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

Lot of folks live in countries where line voltage is 230V. So 50 volts
makes a lot of difference.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

I know nothing about CenTech meters. But I have several \"DT830B\"
meters. Available schematics shows 3 resistors in series for 1000V.
My oldest one have 2 resistors. Newest one have single resistor.
Standard miniature resistors are rated for 250V, one can get
better ones, but I doubt that one can get cheaply 1000V capable
ones. Still, meter is marked as 1000V DC, 700V AC (the same
as old meters).

They eliminated 0.2 cents worth of resistors. Ignore temperature and
voltage coefficient effects. Maybe some of that is mathed out?

Or they bought a better resistor. Until you take it off the board and look at its construction with fairly high tech gear you cant tell what they have done.

Chinese product prices ratchet towards cheap, and the specs ratchet
deep into the lies region. Chinese amps and volts and per cent are
about 10:1 off from SI standards.

Well, the cheap \"DT830B\" were surprisingly accurate. I have
used 4 to measure the same voltage. IIRC the differences
were in last digit and did not exceed 2 counts. They were
bought from different sources at different times, so it
is unlikly to be the same error on all. And they agreed
with better meter. Newest ones seem to have larger
errors, but still well withing specs.

AFAICS biggest problem with cheap meters are test leads,
they tend to fail rather quickly. Second problem is
main switch, which is formed from part of PCB. It
seem to degrade with use. And failing switch can
produce all kinds of wrong results.

Why buy cheap junk test equipment?

Why buy cheap junk anything?

Because cheap isn\'t always junk and junk isn\'t always cheap?
Sometimes it\'s kind of hard to tell.

If the cheap equipment conforms to the relevant standards - which nobody posting here has identified - it shouldn\'t be junk.

Sewage Sweeper wittered on about CAT certification, but didn\'t provide a link to the relevant American underwriter\'s Laboratory specification.

I pointed out that the Underwriters Laboratory are working to align their nationnal specifications with the International Electrotechnical Commission (IEC) specifcations, which Chinese manufacturers aiming at internatioal markets might go for.

Sewage Sweeper naturally ignored this point, probably because he didn\'t understand it.

--
Bill Sloman, Sydney

 

[Anthony William Sloman]

On Monday, January 9, 2023 at 8:33:12 AM UTC+11, Jeroen Belleman wrote:

On 2023-01-08 20:44, John Larkin wrote:
On Sun, 8 Jan 2023 19:02:15 -0000 (UTC), anti...@math.uni.wroc.pl
wrote:

John Larkin <jla...@highlandsnipmetechnology.com> wrote:
On Sat, 7 Jan 2023 01:04:32 -0000 (UTC), anti...@math.uni.wroc.pl
wrote:

Ed Lee <edward....@gmail.com> wrote:
But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

High voltage can destroy resistors, but this seem to be quite fast.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

Lot of folks live in countries where line voltage is 230V. So 50 volts
makes a lot of difference.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

I know nothing about CenTech meters. But I have several \"DT830B\"
meters. Available schematics shows 3 resistors in series for 1000V.
My oldest one have 2 resistors. Newest one have single resistor.
Standard miniature resistors are rated for 250V, one can get
better ones, but I doubt that one can get cheaply 1000V capable
ones. Still, meter is marked as 1000V DC, 700V AC (the same
as old meters).

They eliminated 0.2 cents worth of resistors. Ignore temperature and
voltage coefficient effects. Maybe some of that is mathed out?

Or they bought a better resistor. Until you take it off the board and look at its construction with fairly high tech gear you cant tell what they have done.

Chinese product prices ratchet towards cheap, and the specs ratchet
deep into the lies region. Chinese amps and volts and per cent are
about 10:1 off from SI standards.

Well, the cheap \"DT830B\" were surprisingly accurate. I have
used 4 to measure the same voltage. IIRC the differences
were in last digit and did not exceed 2 counts. They were
bought from different sources at different times, so it
is unlikly to be the same error on all. And they agreed
with better meter. Newest ones seem to have larger
errors, but still well withing specs.

AFAICS biggest problem with cheap meters are test leads,
they tend to fail rather quickly. Second problem is
main switch, which is formed from part of PCB. It
seem to degrade with use. And failing switch can
produce all kinds of wrong results.

Why buy cheap junk test equipment?

Why buy cheap junk anything?

Because cheap isn\'t always junk and junk isn\'t always cheap?
Sometimes it\'s kind of hard to tell.

If the cheap equipment conforms to the relevant standards - which nobody posting here has identified - it shouldn\'t be junk.

Sewage Sweeper wittered on about CAT certification, but didn\'t provide a link to the relevant American underwriter\'s Laboratory specification.

I pointed out that the Underwriters Laboratory are working to align their nationnal specifications with the International Electrotechnical Commission (IEC) specifcations, which Chinese manufacturers aiming at internatioal markets might go for.

Sewage Sweeper naturally ignored this point, probably because he didn\'t understand it.

--
Bill Sloman, Sydney

 

[Anthony William Sloman]

On Monday, January 9, 2023 at 8:33:12 AM UTC+11, Jeroen Belleman wrote:

On 2023-01-08 20:44, John Larkin wrote:
On Sun, 8 Jan 2023 19:02:15 -0000 (UTC), anti...@math.uni.wroc.pl
wrote:

John Larkin <jla...@highlandsnipmetechnology.com> wrote:
On Sat, 7 Jan 2023 01:04:32 -0000 (UTC), anti...@math.uni.wroc.pl
wrote:

Ed Lee <edward....@gmail.com> wrote:
But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

High voltage can destroy resistors, but this seem to be quite fast.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

Lot of folks live in countries where line voltage is 230V. So 50 volts
makes a lot of difference.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

I know nothing about CenTech meters. But I have several \"DT830B\"
meters. Available schematics shows 3 resistors in series for 1000V.
My oldest one have 2 resistors. Newest one have single resistor.
Standard miniature resistors are rated for 250V, one can get
better ones, but I doubt that one can get cheaply 1000V capable
ones. Still, meter is marked as 1000V DC, 700V AC (the same
as old meters).

They eliminated 0.2 cents worth of resistors. Ignore temperature and
voltage coefficient effects. Maybe some of that is mathed out?

Or they bought a better resistor. Until you take it off the board and look at its construction with fairly high tech gear you cant tell what they have done.

Chinese product prices ratchet towards cheap, and the specs ratchet
deep into the lies region. Chinese amps and volts and per cent are
about 10:1 off from SI standards.

Well, the cheap \"DT830B\" were surprisingly accurate. I have
used 4 to measure the same voltage. IIRC the differences
were in last digit and did not exceed 2 counts. They were
bought from different sources at different times, so it
is unlikly to be the same error on all. And they agreed
with better meter. Newest ones seem to have larger
errors, but still well withing specs.

AFAICS biggest problem with cheap meters are test leads,
they tend to fail rather quickly. Second problem is
main switch, which is formed from part of PCB. It
seem to degrade with use. And failing switch can
produce all kinds of wrong results.

Why buy cheap junk test equipment?

Why buy cheap junk anything?

Because cheap isn\'t always junk and junk isn\'t always cheap?
Sometimes it\'s kind of hard to tell.

If the cheap equipment conforms to the relevant standards - which nobody posting here has identified - it shouldn\'t be junk.

Sewage Sweeper wittered on about CAT certification, but didn\'t provide a link to the relevant American underwriter\'s Laboratory specification.

I pointed out that the Underwriters Laboratory are working to align their nationnal specifications with the International Electrotechnical Commission (IEC) specifcations, which Chinese manufacturers aiming at internatioal markets might go for.

Sewage Sweeper naturally ignored this point, probably because he didn\'t understand it.

--
Bill Sloman, Sydney

 

[John Larkin]

On Wed, 11 Jan 2023 11:33:13 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:

On 2023-01-11 05:57, Jan Panteltje wrote:
On a sunny day (Tue, 10 Jan 2023 14:57:00 -0800) it happened Joerg
news@analogconsultants.com> wrote in <k268puFi1h6U1@mid.individual.net>:


Number two: The same guy said that grounded gate circuits in RF stages
make no sense at all. Huh? I did one of those during my very first job
assignment when the ink on my degree was barely dry. And lots before as
a hobbyist.

Sure, used those in some projects.

[...]

Grounded gate --or grounded base-- amplifier stages are very useful!

A cascode is a grounded source stage followed by a grounded gate
stage. That greatly reduces its input capacitance, and so helps
to extend its useful bandwidth. I use cascodes extensively in beam
instrumentation amplifiers in particle accelerators.

IC distributed amplifiers are, I think, always cascodes. Fun and
expensive parts. I used a lot of HMC659\'s in a recent project. I
modestly note that the results made international press.

I also like Norton amplifiers, which are a grounded base stage with
transformer feedback. Those can be designed to have a real 50 Ohm
input resistance, excellent 3rd order intercept, low noise and a
flat gain over a very large bandwidth. High quality radio receivers
invariably have some version of this concept in the first IF stage.
There are examples in the ARRL handbook.

Nortons were a fad for a while. I never understood why. Do people
still make them?

Darlington MMICS are great. Some have NFs below 1 dB.

Jeroen Belleman

 

[John Larkin]

On Wed, 11 Jan 2023 11:33:13 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:

On 2023-01-11 05:57, Jan Panteltje wrote:
On a sunny day (Tue, 10 Jan 2023 14:57:00 -0800) it happened Joerg
news@analogconsultants.com> wrote in <k268puFi1h6U1@mid.individual.net>:


Number two: The same guy said that grounded gate circuits in RF stages
make no sense at all. Huh? I did one of those during my very first job
assignment when the ink on my degree was barely dry. And lots before as
a hobbyist.

Sure, used those in some projects.

[...]

Grounded gate --or grounded base-- amplifier stages are very useful!

A cascode is a grounded source stage followed by a grounded gate
stage. That greatly reduces its input capacitance, and so helps
to extend its useful bandwidth. I use cascodes extensively in beam
instrumentation amplifiers in particle accelerators.

IC distributed amplifiers are, I think, always cascodes. Fun and
expensive parts. I used a lot of HMC659\'s in a recent project. I
modestly note that the results made international press.

I also like Norton amplifiers, which are a grounded base stage with
transformer feedback. Those can be designed to have a real 50 Ohm
input resistance, excellent 3rd order intercept, low noise and a
flat gain over a very large bandwidth. High quality radio receivers
invariably have some version of this concept in the first IF stage.
There are examples in the ARRL handbook.

Nortons were a fad for a while. I never understood why. Do people
still make them?

Darlington MMICS are great. Some have NFs below 1 dB.

Jeroen Belleman

 

[John Larkin]

On Wed, 11 Jan 2023 11:33:13 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:

On 2023-01-11 05:57, Jan Panteltje wrote:
On a sunny day (Tue, 10 Jan 2023 14:57:00 -0800) it happened Joerg
news@analogconsultants.com> wrote in <k268puFi1h6U1@mid.individual.net>:


Number two: The same guy said that grounded gate circuits in RF stages
make no sense at all. Huh? I did one of those during my very first job
assignment when the ink on my degree was barely dry. And lots before as
a hobbyist.

Sure, used those in some projects.

[...]

Grounded gate --or grounded base-- amplifier stages are very useful!

A cascode is a grounded source stage followed by a grounded gate
stage. That greatly reduces its input capacitance, and so helps
to extend its useful bandwidth. I use cascodes extensively in beam
instrumentation amplifiers in particle accelerators.

IC distributed amplifiers are, I think, always cascodes. Fun and
expensive parts. I used a lot of HMC659\'s in a recent project. I
modestly note that the results made international press.

I also like Norton amplifiers, which are a grounded base stage with
transformer feedback. Those can be designed to have a real 50 Ohm
input resistance, excellent 3rd order intercept, low noise and a
flat gain over a very large bandwidth. High quality radio receivers
invariably have some version of this concept in the first IF stage.
There are examples in the ARRL handbook.

Nortons were a fad for a while. I never understood why. Do people
still make them?

Darlington MMICS are great. Some have NFs below 1 dB.

Jeroen Belleman