# DC&AC Watt meter

#### Teyvanai

Joined Dec 6, 2015
24
A]] Circuit-to make watt meter:- I wanted to connect (1) 1 to 12 volt DC voltage; one input and the ( 2nd) input
DC 1mA to1.2 Amp current then mix (1&2 inputs ) =DC watts read on Panel meter panel or digital .

B]] Circuit-make watt meter:-what wanted to connect (1) 1 to 12 volt AC voltage; one input and the ( 2nd) input AC
1mA to 1.2 Amp current then mix (1&2 inputs ) =AC watts read on Panel meter or digital

Please where A and B use the same watt meter

Respectfully
I have been searching for circuit I can modify '''NO LUCK''
I have even talked to the IC suppliers ''still NO LUCK ''

#### Ya’akov

Joined Jan 27, 2019
6,272
The easiest way to do this will be with a small MCU, a couple of ADCs, and a current sensor.

#### Teyvanai

Joined Dec 6, 2015
24
Yaakov
Respectfully thank you.
Are you reffering to a MCU as micro controller ?
Any circuit ideas - will help..

#### Ya’akov

Joined Jan 27, 2019
6,272
Yaakov
Respectfully thank you.
Are you reffering to a MCU as micro controller ?
Any circuit ideas - will help..
Yes, a microcontroller. Measuring voltage and current is easy, a circuit to power math is far more complicated than a little MCU which would make the whole thing easy.

What is the application?

#### Teyvanai

Joined Dec 6, 2015
24
Thank you for your experience and time in helping me
the problem is combing Dc volts and current to get the wanted Watts reading ?
as original search I could not get no help

#### Papabravo

Joined Feb 24, 2006
18,980
Thank you for your experience and time in helping me
the problem is combing Dc volts and current to get the wanted Watts reading ?
as original search I could not get no help
It is possible that your search was too narrow. If I were doing it I would look at all classes of power measurement devices, from lab quality to hand held. If I was really serious I would get one or two and do a teardown to learn all that I possibly could. You don't really expect people to spray valuable IP all over the internet -- do you?

#### Ya’akov

Joined Jan 27, 2019
6,272
Thank you for your experience and time in helping me
the problem is combing Dc volts and current to get the wanted Watts reading ?
as original search I could not get no help
You could do the job with an analog circuit, or with discrete digital logic, but it would be so much more complicated than doing it in software that it hardly makes sense unless your application demands it—and I can't imagine one that does.

#### Teyvanai

Joined Dec 6, 2015
24
thank you
then I must keep searching until I do find
build up from bits and pieces = DC/AC watt meter

#### KeithWalker

Joined Jul 10, 2017
2,456
That is an extremely wide range of power you specified; 1mW to 14.4W. What accuracy and response time are you hoping for?
There are several ways you could do this, but they are all quite complicated, and I suspect, beyond your engineering capabilities.

#### Teyvanai

Joined Dec 6, 2015
24
I did not say that:-
this is said ! >>
A]] Circuit-to make watt meter:- I wanted to connect (1) 1to12volt DC voltage; one input and the ( 2nd) input
DC 1mA to1.2 Amp current then mix (1&2 inputs ) =DC watts read on Panel meter panel or digital .

B]] Circuit-make watt meter:-what wanted to connect (1) 1to12volt AC voltage; one input and the ( 2nd) input AC
1mAto1.2 Amp current then mix (1&2 inputs ) =AC watts read on Panel meter or digital

Please where A and B use the same watt meter

Respectfully
I have been searching for circuit I can modify '''NO LUCK''
I have even talked to the IC suppliers ''still NO LUCK ''

#### Papabravo

Joined Feb 24, 2006
18,980
I did not say that:-
this is said ! >>
A]] Circuit-to make watt meter:- I wanted to connect (1) 1to12volt DC voltage; one input and the ( 2nd) input
DC 1mA to1.2 Amp current then mix (1&2 inputs ) =DC watts read on Panel meter panel or digital .

B]] Circuit-make watt meter:-what wanted to connect (1) 1to12volt AC voltage; one input and the ( 2nd) input AC
1mAto1.2 Amp current then mix (1&2 inputs ) =AC watts read on Panel meter or digital

Please where A and B use the same watt meter

Respectfully
I have been searching for circuit I can modify '''NO LUCK''
I have even talked to the IC suppliers ''still NO LUCK ''
Do you somehow believe that repeating your original post is helpful in getting you to a solution that is acceptable to you. Take our advice or don't take it, but don't insult our intelligence by repeating yourself.

#### KeithWalker

Joined Jul 10, 2017
2,456
Power is voltage multiplied by current. The current must be converted to a voltage using a shunt. There is no simple analog circuit that will multiply two voltages together accurately. You would need two accurate logarithmic amplifiers and a summing amplifier or a Hall Effect quadrature device. to achieve that. You could use a bolometer, as used for microwave power measurements but you would need to compensate for ambient temperature and allow for nonlinearities in the element. all of those solutions are quite complicated. Not the kind of thing the average hobbyist could throw together on the kitchen table. The range of power you want to measure is extreme which would complicate the solution even more.
I asked you two simple questions Your answer to both of them will give me some idea of what to suggest for a solution to your question.

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#### Teyvanai

Joined Dec 6, 2015
24
KeithWalker
all I want is a watt meter to measure at its input (1) dc/ac 1 volt up to 12 voltage at input (2) dc/ac
current from 1mA up to 1.2 amps output (3) resultant in watts read on a digital meter [[[at first I did not work what the resultant watts would be [[[ I apologize to every member]] = 14.4 Watts
Thank you all your support !

#### boostbuck

Joined Oct 5, 2017
222
There are a number of circuits for non-digital Solar MPPT controllers that measure wattage as a multiplication of current and voltage - this might be a starting point for the DC side of your project.

#### Teyvanai

Joined Dec 6, 2015
24
boostbuck
thank you Sir .
for you help - I did not know about the MPPT - seriously i have contacted the IC suppliers and no help
for my watt meter project and i also search google no help ..
your respect Sir please how can we get to use AC volts and current

#### Ya’akov

Joined Jan 27, 2019
6,272
If you really want help you can answer my question from before: what is the application for this? What will it be used for?

#### KeithWalker

Joined Jul 10, 2017
2,456
KeithWalker
all I want is a watt meter to measure at its input (1) dc/ac 1 volt up to 12 voltage at input (2) dc/ac
current from 1mA up to 1.2 amps output (3) resultant in watts read on a digital meter [[[at first I did not work what the resultant watts would be [[[ I apologize to every member]] = 14.4 Watts
Thank you all your support !
Yes, you have stated that in three separate posts in this thread but you still have not answered my questions about the required accuracy an speed of response. Without that information I can not suggest any solution. From your responses I am beginning to think that you do not understand anything about electronic measurements.

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#### MisterBill2

Joined Jan 23, 2018
12,700
The problem is that the TS does not understand what we are asking when we ask about what the application is. Thus we get a repeat of the original statement. My suggestion is to use an accurate 16 or 24 bit A/D converter to measure the voltage and another one reading a shunt resistor to measure the current. If both converters have serial outputs then isolation should be much simpler. Than a processor to calculate the values of voltage and current and drive a display.
The hardware design and software creation can be done with components from a number of different suppliers. Every step of the project is fairly obvious, but that does not make it simple or easy. I have an associate who could provide the complete design possibly for as little as $9500.. OR the TS could contact the Fluke Instrument company and purchase a working, accurate device that will do all of that for less than$3000. And it will be a durable package that will serve well for many years.

#### Papabravo

Joined Feb 24, 2006
18,980
The problem is that the TS does not understand what we are asking when we ask about what the application is. Thus we get a repeat of the original statement. My suggestion is to use an accurate 16 or 24 bit A/D converter to measure the voltage and another one reading a shunt resistor to measure the current. If both converters have serial outputs then isolation should be much simpler. Than a processor to calculate the values of voltage and current and drive a display.
The hardware design and software creation can be done with components from a number of different suppliers. Every step of the project is fairly obvious, but that does not make it simple or easy. I have an associate who could provide the complete design possibly for as little as $9500.. OR the TS could contact the Fluke Instrument company and purchase a working, accurate device that will do all of that for less than$3000. And it will be a durable package that will serve well for many years.
Careful you might start a bidding war with a consequent race to the bottom. Just let this one go.