Volt/Ammeter Question.

[~misfit~]

Hi gang, sorry to keep bothering you with questions.

I just took delivery of one of these;
http://www.aliexpress.com/item/1pcs-Professional-DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Amp-Dual-Digital-Volt-Meter-Gauge/32612148403.html

It's a 5V - 30V / 10A meter that I want to use in a recycle-built bench
power supply that I'm making using a 20V laptop brick and an adjustable
voltage / current LED driver module rated to 30V and 40W.

Trouble is there are two connectors on the meter, light-gauge red / black
and heavier gauge red / black / blue wires and no connection diagram
included. Any help on how to connect it to my 'bench supply' appreciated.

I'm guessing that the light red / black are for parallel connection to load
as a voltmeter and the heavier wires are for series connection to load for
ammeter but don't know if I'm right and wether the blue wire is 'out' for
positive or negative - I assume positive. I could just 'suck it and see'
(and will if I don't hear back fairly soon <g&gt but would prefer
pre-knowldge if possible. It'd be a shame to cook it and then have to wait
another two weeks for a second one.

Cheers,
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

 

[Phil Allison]

~misfit~ wrote:

I just took delivery of one of these;
http://www.aliexpress.com/item/1pcs-Professional-DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Amp-Dual-Digital-Volt-Meter-Gauge/32612148403.html

It's a 5V - 30V / 10A meter that I want to use in a recycle-built bench
power supply that I'm making using a 20V laptop brick and an adjustable
voltage / current LED driver module rated to 30V and 40W.

Trouble is there are two connectors on the meter, light-gauge red / black
and heavier gauge red / black / blue wires and no connection diagram
included. Any help on how to connect it to my 'bench supply' appreciated.

I'm guessing that the light red / black are for parallel connection to load
as a voltmeter and the heavier wires are for series connection to load for
ammeter but don't know if I'm right and wether the blue wire is 'out' for
positive or negative - I assume positive. I could just 'suck it and see'
(and will if I don't hear back fairly soon <g&gt but would prefer
pre-knowldge if possible. It'd be a shame to cook it and then have to wait
another two weeks for a second one.

** Far more likely, the light red/black wires are for the meter itself: 4.5 to 30V supply, red = positive.

The heavy red/black/blue wires are for measurement: red = 100V, blue = 10A current with black as common. The red and blue LED displays are the clue.

Check if the black wires are linked internally, ie they test zero ohms.


..... Phil

 

[Computer Nerd Kev]

~misfit~ <shaun.at.pukekohe@gmail.com> wrote:

Hi gang, sorry to keep bothering you with questions.

I just took delivery of one of these;
http://www.aliexpress.com/item/1pcs-Professional-DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Amp-Dual-Digital-Volt-Meter-Gauge/32612148403.html

It's a 5V - 30V / 10A meter that I want to use in a recycle-built bench
power supply that I'm making using a 20V laptop brick and an adjustable
voltage / current LED driver module rated to 30V and 40W.

LED driver module? Oh well good luck. If it really is independently
adjustable voltage and current then it might work, but if it's
designed for LEDs, the designers probably won't have worried much
about noise on the output.

Trouble is there are two connectors on the meter, light-gauge red / black
and heavier gauge red / black / blue wires and no connection diagram
included. Any help on how to connect it to my 'bench supply' appreciated.

I'm guessing that the light red / black are for parallel connection to load
as a voltmeter and the heavier wires are for series connection to load for
ammeter but don't know if I'm right and wether the blue wire is 'out' for
positive or negative - I assume positive. I could just 'suck it and see'
(and will if I don't hear back fairly soon <g&gt but would prefer
pre-knowldge if possible. It'd be a shame to cook it and then have to wait
another two weeks for a second one.

I couldn't say for sure, but I expect the small wires are the power for the
meter itself, and the thick wires are all for taking the reading.

At a guess, the thick Red wire is for voltage (which it displays in Red),
the Blue wire is for the Current Shunt (as current is displayed in Blue),
and the thick Black wire is ground.

The Thick Red wire would go to the bench supply's positive output, the
thick Black wire to the ground connection of the LED driver, and the Blue
wire to the Bench supply's Ground connection.

Measure with a multimeter to see that there is a very low resistance
between the thick Blue and Black wires, and a high resistance between
the thick Red wire and both the thick Black and the thick Blue wires.

Low = Less than 3R
High = More than 100K

The small wires should go to the output of the laptop power supply, in
parallel with the LED driver, as long as the laptop supply doesn't
(by some strange occurrence) supply more than 30V (the maximum supply
voltage they say the meter's rated for).

--
__ __
#_ < |\| |< _#

 

[Jasen Betts]

On 2016-04-16, ~misfit~ <shaun.at.pukekohe@gmail.com> wrote:

Hi gang, sorry to keep bothering you with questions.

I just took delivery of one of these;
http://www.aliexpress.com/item/1pcs-Professional-DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Amp-Dual-Digital-Volt-Meter-Gauge/32612148403.html

I've got a few of them here.

It's a 5V - 30V / 10A meter that I want to use in a recycle-built bench
power supply that I'm making using a 20V laptop brick and an adjustable
voltage / current LED driver module rated to 30V and 40W.

Trouble is there are two connectors on the meter, light-gauge red / black
and heavier gauge red / black / blue wires and no connection diagram
included. Any help on how to connect it to my 'bench supply' appreciated.

I'm guessing that the light red / black are for parallel connection to load
as a voltmeter and the heavier wires are for series connection to load for
ammeter but don't know if I'm right and wether the blue wire is 'out' for
positive or negative - I assume positive. I could just 'suck it and see'
(and will if I don't hear back fairly soon <g&gt but would prefer
pre-knowldge if possible. It'd be a shame to cook it and then have to wait
another two weeks for a second one.

Actually the thin wires are to power the LEDs and the measuring
circuit, the thick ones are for the metering.

the ammeter in in series with the negative supply.
blue being the negative output, red being the common positive and black the
negative input.

I could have blue and black transposed, if the amps always reads zero
swap them (the device will not be damaged).

connect the thin wires to your 20V input (the thin black is internally
connected to the thick black, so you can't use a DC-DC converter that
generates a voltage between negative in ans negative out, most don't)

--
\_(ツ)_

 

[~misfit~]

Once upon a time on usenet ~misfit~ wrote:
[sipped]

It's got a 470uf / 35V cap and a choke made up of a 15mm ferrite ring
with ~50 turns of wire on it as part of the output filtering. I'm not
sure if the main switching step-dowm voltage converter is an LM259
(150Hz) or an XL4005 (300Hz) as there's a heatsink on it (as well as
a bigger heatsink on the other side of the PCB). The module is 55 x
36mm and comes with 4 x 10mm stand-offs fitted.

Gah! Obviously that should read 150KHz and 300KHz respectively for the LM259
and XL4005.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

 

[~misfit~]

Once upon a time on usenet Computer Nerd Kev wrote:

~misfit~ <shaun.at.pukekohe@gmail.com> wrote:
Hi gang, sorry to keep bothering you with questions.

I just took delivery of one of these;
http://www.aliexpress.com/item/1pcs-Professional-DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Amp-Dual-Digital-Volt-Meter-Gauge/32612148403.html

It's a 5V - 30V / 10A meter that I want to use in a recycle-built
bench power supply that I'm making using a 20V laptop brick and an
adjustable voltage / current LED driver module rated to 30V and 40W.

LED driver module? Oh well good luck. If it really is independently
adjustable voltage and current then it might work, but if it's
designed for LEDs, the designers probably won't have worried much
about noise on the output.

Yeah it really is. I've used it on several high-power LEDs ranging from a 3W
IR to a 30W COB led. Testing with the DMM shows that adjusting the trimpots
adjusts the voltage and amperage respectively without changing the other
parameter.

It's got a 470uf / 35V cap and a choke made up of a 15mm ferrite ring with
~50 turns of wire on it as part of the output filtering. I'm not sure if the
main switching step-dowm voltage converter is an LM259 (150Hz) or an XL4005
(300Hz) as there's a heatsink on it (as well as a bigger heatsink on the
other side of the PCB). The module is 55 x 36mm and comes with 4 x 10mm
stand-offs fitted.

Anyway if noise might be an issue I can always throw a few (more) caps
across the output, maybe in a cascade arrangement and another choke. After
all I'm making this thing.

Trouble is there are two connectors on the meter, light-gauge red /
black and heavier gauge red / black / blue wires and no connection
diagram included. Any help on how to connect it to my 'bench supply'
appreciated.

I'm guessing that the light red / black are for parallel connection
to load as a voltmeter and the heavier wires are for series
connection to load for ammeter but don't know if I'm right and
wether the blue wire is 'out' for positive or negative - I assume
positive. I could just 'suck it and see' (and will if I don't hear
back fairly soon <g&gt but would prefer pre-knowldge if possible.
It'd be a shame to cook it and then have to wait another two weeks
for a second one.

I couldn't say for sure, but I expect the small wires are the power
for the meter itself, and the thick wires are all for taking the
reading.

At a guess, the thick Red wire is for voltage (which it displays in
Red), the Blue wire is for the Current Shunt (as current is displayed
in Blue), and the thick Black wire is ground.

The Thick Red wire would go to the bench supply's positive output, the
thick Black wire to the ground connection of the LED driver, and the
Blue wire to the Bench supply's Ground connection.

Measure with a multimeter to see that there is a very low resistance
between the thick Blue and Black wires, and a high resistance between
the thick Red wire and both the thick Black and the thick Blue wires.

Low = Less than 3R
High = More than 100K

The small wires should go to the output of the laptop power supply, in
parallel with the LED driver, as long as the laptop supply doesn't
(by some strange occurrence) supply more than 30V (the maximum supply
voltage they say the meter's rated for).

Thanks. As mentioned the laptop PSU is rated at 20V and I measure 20.4V as a
no-load output.

Cheers,
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

 

[~misfit~]

Once upon a time on usenet Phil Allison wrote:

~misfit~ wrote:



I just took delivery of one of these;
http://www.aliexpress.com/item/1pcs-Professional-DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Amp-Dual-Digital-Volt-Meter-Gauge/32612148403.html

It's a 5V - 30V / 10A meter that I want to use in a recycle-built
bench power supply that I'm making using a 20V laptop brick and an
adjustable voltage / current LED driver module rated to 30V and 40W.

Trouble is there are two connectors on the meter, light-gauge red /
black and heavier gauge red / black / blue wires and no connection
diagram included. Any help on how to connect it to my 'bench supply'
appreciated.

I'm guessing that the light red / black are for parallel connection
to load as a voltmeter and the heavier wires are for series
connection to load for ammeter but don't know if I'm right and
wether the blue wire is 'out' for positive or negative - I assume
positive. I could just 'suck it and see' (and will if I don't hear
back fairly soon <g&gt but would prefer pre-knowldge if possible.
It'd be a shame to cook it and then have to wait another two weeks
for a second one.


** Far more likely, the light red/black wires are for the meter
itself: 4.5 to 30V supply, red = positive.

The heavy red/black/blue wires are for measurement: red = 100V, blue
= 10A current with black as common. The red and blue LED displays are
the clue.

Check if the black wires are linked internally, ie they test zero
ohms.

Cheers Phil, appreciate the advice. Apologies for the late reply, yet
another case of real life intruding.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

 

[~misfit~]

Once upon a time on usenet Jasen Betts wrote:

On 2016-04-16, ~misfit~ <shaun.at.pukekohe@gmail.com> wrote:
Hi gang, sorry to keep bothering you with questions.

I just took delivery of one of these;
http://www.aliexpress.com/item/1pcs-Professional-DC-100V-10A-Voltmeter-Ammeter-Blue-Red-LED-Amp-Dual-Digital-Volt-Meter-Gauge/32612148403.html

I've got a few of them here.

It's a 5V - 30V / 10A meter that I want to use in a recycle-built
bench power supply that I'm making using a 20V laptop brick and an
adjustable voltage / current LED driver module rated to 30V and 40W.

Trouble is there are two connectors on the meter, light-gauge red /
black and heavier gauge red / black / blue wires and no connection
diagram included. Any help on how to connect it to my 'bench supply'
appreciated.

I'm guessing that the light red / black are for parallel connection
to load as a voltmeter and the heavier wires are for series
connection to load for ammeter but don't know if I'm right and
wether the blue wire is 'out' for positive or negative - I assume
positive. I could just 'suck it and see' (and will if I don't hear
back fairly soon <g&gt but would prefer pre-knowldge if possible.
It'd be a shame to cook it and then have to wait another two weeks
for a second one.

Actually the thin wires are to power the LEDs and the measuring
circuit, the thick ones are for the metering.

the ammeter in in series with the negative supply.
blue being the negative output, red being the common positive and
black the negative input.

I could have blue and black transposed, if the amps always reads zero
swap them (the device will not be damaged).

connect the thin wires to your 20V input (the thin black is internally
connected to the thick black, so you can't use a DC-DC converter that
generates a voltage between negative in ans negative out, most don't)

Thanks a lot Jasen, good to know. I might explain it in the feedback I give
on AE (once I know for sure).
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)