In article <tpvek2$1fs$1@gioia.aioe.org>, <antispam@math.uni.wroc.pl> wrote:
>Mike Monett VE3BTI <spamme@not.com> wrote:
>> antispam@math.uni.wroc.pl wrote:
>>
>> >> Why buy cheap junk anything?
>> >
>> > I many cases buying a product is cheapest way to get info
>> > if it is worth anything. In bygone era one could relay
>> > on brands, but this is no longer the case, one can buy
>> > product from expensive brand and get exactly the same
>> > junk as cheap one.
>> >
>> > --
>> > Waldek Hebisch
>>
>> I agree. I have bought many DT830 multimeters and found some die for no
>> reason. I also have bought many to give to friends.
>>
>> Since then, I have come across the very best multimeter I have ever seen in
>> my 80 years. It is called the RichMeter RM109.
>>
>> It has very fast autoranging with manual option, 4 1/2 digit, 1 KVDC range,
>> 1MV range with resolution down to 1 microvolt, can measure down to 1e-13A
>> with external 10MEG resistor, measures frequency, capacitance, built-in
>> square wave signal generator. Unblievable performance in a small 5" X 2.5"
>> package.
>>
>> Specifications
>>
>> https://richmeters.en.made-in-china.com/product/rdvAUnjKZocY/China-RM109-
>> Digital-Multimeter-9999-Counts-Square-Wave-Auto-Ranging.html
>>
>> US $22.87
>> https://www.aliexpress.com/item/1005001966216610.html
>>
>> A companion model measures temperature.
>
>That looks quite similar to Aneng AN8009 that I have. They are
>probably based on the same chip.
I'm wildly enthousiastic about the Aneng 8009
The things that are better than some/all other meters I had before:
1. zipped case to keep the leads together and the meter
2. leads can be plugged in in the case, ready for use.
3. plethora of leads. different pins, banana plugs, and alligator
clips.
4. more precision
5. back lighting
6 auto turn off
7 AA batteries instead of 9V
8 small form factor, the size of the display is what matters.
9 battery compartment shuts with metal screws (!)
10 survived voltage on a current range 1]
11 likely to survive drops on concrete floor (no experiments).
1] Fair to say the 10 Ampere fuse blew and I can't find a spare.
I discovered a disadvantage, a lack of ranges between
###.# mA and ##.## uA (I'd like #.### mA ) today.
Once you have the production line in place it makes no sense to
detoriate the product. Why would you go to the trouble replacing
metal screws seating in brass by parkers cutting into plastic?
Only USA bean counters kill a product like the DEC
Alpha.
That is a 20 euro meter.
>--
> Waldek Hebisch
Groetjes Albert
--
Don't praise the day before the evening. One swallow doesn't make spring.
You must not say "hey" before you have crossed the bridge. Don't sell the
hide of the bear until you shot it. Better one bird in the hand than ten in
the air. First gain is a cat spinning. - the Wise from Antrim -
Reply by ●January 15, 20232023-01-15
Mike Monett VE3BTI <spamme@not.com> wrote:
> antispam@math.uni.wroc.pl wrote:
>
> > That looks quite similar to Aneng AN8009 that I have. They are
> > probably based on the same chip.
> >
> > --
> > Waldek Hebisch
> >
>
> You are right. It looks identical. Not only the same chip, it has the same
> case with different branding. Somewhere there has to be a source that
> supplies these meters to different companies for distribution.
"Looks identical" does not mean that they are identical. DT830B bought
at the same time had different PCB. I looked at few Chinese USB
chargers and power supplies: from outside you had pair of identical
(or _very_ similar) things, inside were different PCB-s. Schematics
probably were very similar or identical, but they clearly came from
different production lines.
There is a lot of rebranding, but people here probably underestimate
size of Chinese market. It is big enough to support several independent
manufacturers.
--
Waldek Hebisch
Reply by whit3rd●January 15, 20232023-01-15
On Saturday, January 14, 2023 at 8:15:57 AM UTC-8, John Larkin wrote:
> On Sat, 14 Jan 2023 15:06:40 -0000 (UTC), anti...@math.uni.wroc.pl
> wrote:
>
> >John Larkin <jla...@highlandsnipmetechnology.com> wrote:
> >> Why buy cheap junk anything?
> >
> >I many cases buying a product is cheapest way to get info
> >if it is worth anything. In bygone era one could relay
> >on brands, but this is no longer the case...
> I don't understand spending hours to save a few dollars and maybe get
> something flakey.
Every purchase is on the 'maybe get somethng flakey' basis.
Reliance on brands, for instance, has failure modes.
>
> Some people are just obcessive about saving money. They clip coupons,
> search for deals, buy and return stuff.
Well, if it doesn't get returned, the supplier will never know it isn't a good product;
that's part of the mass-market's feedback loop on quality control. Participate,
or don't expect good quality control.
> Fluke and Extech and Rigol are good.
This week, probably. Past experience, though, says that doesn't have to
last forever.
Reply by Mike Monett VE3BTI●January 14, 20232023-01-14
antispam@math.uni.wroc.pl wrote:
> That looks quite similar to Aneng AN8009 that I have. They are
> probably based on the same chip.
>
> --
> Waldek Hebisch
>
You are right. It looks identical. Not only the same chip, it has the same
case with different branding. Somewhere there has to be a source that
supplies these meters to different companies for distribution.
Remarkable design. No need for DT830 any more
--
MRM
Reply by ●January 14, 20232023-01-14
Mike Monett VE3BTI <spamme@not.com> wrote:
> antispam@math.uni.wroc.pl wrote:
>
> >> Why buy cheap junk anything?
> >
> > I many cases buying a product is cheapest way to get info
> > if it is worth anything. In bygone era one could relay
> > on brands, but this is no longer the case, one can buy
> > product from expensive brand and get exactly the same
> > junk as cheap one.
> >
> > --
> > Waldek Hebisch
>
> I agree. I have bought many DT830 multimeters and found some die for no
> reason. I also have bought many to give to friends.
>
> Since then, I have come across the very best multimeter I have ever seen in
> my 80 years. It is called the RichMeter RM109.
>
> It has very fast autoranging with manual option, 4 1/2 digit, 1 KVDC range,
> 1MV range with resolution down to 1 microvolt, can measure down to 1e-13A
> with external 10MEG resistor, measures frequency, capacitance, built-in
> square wave signal generator. Unblievable performance in a small 5" X 2.5"
> package.
>
> Specifications
>
> https://richmeters.en.made-in-china.com/product/rdvAUnjKZocY/China-RM109-
> Digital-Multimeter-9999-Counts-Square-Wave-Auto-Ranging.html
>
> US $22.87
> https://www.aliexpress.com/item/1005001966216610.html
>
> A companion model measures temperature.
That looks quite similar to Aneng AN8009 that I have. They are
probably based on the same chip.
--
Waldek Hebisch
Reply by John Larkin●January 14, 20232023-01-14
On Sat, 14 Jan 2023 18:05:36 -0000 (UTC), Mike Monett VE3BTI
<spamme@not.com> wrote:
>antispam@math.uni.wroc.pl wrote:
>
>>> Why buy cheap junk anything?
>>
>> I many cases buying a product is cheapest way to get info
>> if it is worth anything. In bygone era one could relay
>> on brands, but this is no longer the case, one can buy
>> product from expensive brand and get exactly the same
>> junk as cheap one.
>>
>> --
>> Waldek Hebisch
>
>I agree. I have bought many DT830 multimeters and found some die for no
>reason. I also have bought many to give to friends.
>
>Since then, I have come across the very best multimeter I have ever seen in
>my 80 years. It is called the RichMeter RM109.
>
>It has very fast autoranging with manual option, 4 1/2 digit, 1 KVDC range,
>1MV range with resolution down to 1 microvolt, can measure down to 1e-13A
>with external 10MEG resistor, measures frequency, capacitance, built-in
>square wave signal generator. Unblievable performance in a small 5" X 2.5"
>package.
>
>Specifications
>
>https://richmeters.en.made-in-china.com/product/rdvAUnjKZocY/China-RM109-
>Digital-Multimeter-9999-Counts-Square-Wave-Auto-Ranging.html
>
>US $22.87
>https://www.aliexpress.com/item/1005001966216610.html
>
>A companion model measures temperature.
Most DVMs are 10 meg input on volts ranges, so even cheap ones are
picoammeters.
Reply by Mike Monett VE3BTI●January 14, 20232023-01-14
antispam@math.uni.wroc.pl wrote:
>> Why buy cheap junk anything?
>
> I many cases buying a product is cheapest way to get info
> if it is worth anything. In bygone era one could relay
> on brands, but this is no longer the case, one can buy
> product from expensive brand and get exactly the same
> junk as cheap one.
>
> --
> Waldek Hebisch
I agree. I have bought many DT830 multimeters and found some die for no
reason. I also have bought many to give to friends.
Since then, I have come across the very best multimeter I have ever seen in
my 80 years. It is called the RichMeter RM109.
It has very fast autoranging with manual option, 4 1/2 digit, 1 KVDC range,
1MV range with resolution down to 1 microvolt, can measure down to 1e-13A
with external 10MEG resistor, measures frequency, capacitance, built-in
square wave signal generator. Unblievable performance in a small 5" X 2.5"
package.
Specifications
https://richmeters.en.made-in-china.com/product/rdvAUnjKZocY/China-RM109-
Digital-Multimeter-9999-Counts-Square-Wave-Auto-Ranging.html
US $22.87
https://www.aliexpress.com/item/1005001966216610.html
A companion model measures temperature.
--
MRM
Reply by Ed Lee●January 14, 20232023-01-14
On Saturday, January 14, 2023 at 7:06:49 AM UTC-8, anti...@math.uni.wroc.pl wrote:
> John Larkin <jla...@highlandsnipmetechnology.com> 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?
> > >>
> > >> 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?
> I would not lablel my "DT830B"-s as junk, they work well enough.
> As I wrote, they are accurate. They are small and light.
> And the measurement ranges are better suited to electronics
> that many more expensive meters (for example many meters lack
> 200uA range). I like ranges set by switch and lack of automatic
> turn-off (so meter does not turn off half into long measurement).
> Featurewise, I would like separate power switch, but that would
> be hard to add given compact form factor.
The CenTech meter is almost identical but with a power switch. However, the switch is really small and unreliable. I am thinking about adding an external switch.
I want auto-off after 24 hours. Sometimes, i left it on for days.
Reply by John Larkin●January 14, 20232023-01-14
On Sat, 14 Jan 2023 15:06:40 -0000 (UTC), antispam@math.uni.wroc.pl
wrote:
>John Larkin <jlarkin@highlandsnipmetechnology.com> wrote:
>> On Sun, 8 Jan 2023 19:02:15 -0000 (UTC), antispam@math.uni.wroc.pl
>> wrote:
>>
>> >John Larkin <jlarkin@highlandsnipmetechnology.com> wrote:
>> >> On Sat, 7 Jan 2023 01:04:32 -0000 (UTC), antispam@math.uni.wroc.pl
>> >> wrote:
>> >>
>> >> >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).
>> >>
>> >> They eliminated 0.2 cents worth of resistors. Ignore temperature and
>> >> voltage coefficient effects. Maybe some of that is mathed out?
>> >>
>> >> 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?
>
>I would not lablel my "DT830B"-s as junk, they work well enough.
>As I wrote, they are accurate. They are small and light.
>And the measurement ranges are better suited to electronics
>that many more expensive meters (for example many meters lack
>200uA range). I like ranges set by switch and lack of automatic
>turn-off (so meter does not turn off half into long measurement).
>Featurewise, I would like separate power switch, but that would
>be hard to add given compact form factor.
>
>Concerning test leads, when they fail I take new ones, that is
>minor annoyance. Basically it means that one has to factor
>cost of replacement leads to price of the meter. Concerning
>PCB switch, it means that meter is less durable than meters with
>real switch. OTOH looking at teardowns of various meters I
>saw no with real switch. Maybe there are some, but I do not
>expect to get meter with real switch below $60 (or should
>I write $600?).
>
>To put it differently, for simple measurements I do not see
>anything better, so why pay more? When I need better accuracy
>or need more than "DT830B" can do I use better meters
>(slightly better "DT9205A" or Aneng 8000 series).
>
>BTW: Some folks probably would say that Anengs are
>"cheap junk", they costed me below $20 per piece.
>Yet they have resolution better than much more expensive
>stuff. They look solid and people who tested them say
>they are solid.
>
>> Why buy cheap junk anything?
>
>I many cases buying a product is cheapest way to get info
>if it is worth anything. In bygone era one could relay
>on brands, but this is no longer the case, one can buy
>product from expensive brand and get exactly the same
>junk as cheap one.
I don't understand spending hours to save a few dollars and maybe get
something flakey.
Some people are just obcessive about saving money. They clip coupons,
search for deals, buy and return stuff.
Fluke and Extech and Rigol are good.