voltage of dimmer output not reading same on two different DVM\'s...

[jurb...@gmail.com]

>\" true RMS \" = DC equivalent value for the *heating* effect on a resistance.

Known. but a DC meter might not be set up for that.To be, it would have to have some sort of filter and they don\'t really do that because they don\'t want the load. I think I told the guy to get a resistor and a cap, damn such uncritical values really, cana be 10K and a 47uF, or a 470 and a 10uF. It just doesn\'t matter if that meter has an input of 10 megs.

Of course TRMS might come in handy for an incandescent or some sort of heating element, but for LED it is out of the game.

I would think most LED dimmers say rated 400 watts (?) would be ready for multiple LEDs in parallel. This absolutely requires the max voltage delivered with PWM or they will not come on or dim at the same rate.

So he was trying to measure PWM on a DC scale, might work on an old style meter with a real meter, but not on this.

The first time TRMS did me any good was on TVs. Of all things, the filament winding of the power transformer opened up. I decided rather than change it, run the filament off the flyback. So I did and I wound the wire around the core and the meter read about 6.3 or so on TRMS and I connected it. ZAM it worked.

I found out that with that half sine, 70KHz wave repeating at 15.7Khz came to the right voltage at 22 volts peak to peak off the fly.

I had adventures in that. Shorted H-K ? We I got a winding for that. Panasonics seemed to be really affected by the capacitance though I tried to keep it low. So I EQed the video output circuit for it, just a cap in the emitter of one of the transistors. Short intermittent ? Fine, I just put like a 4.7 K in there to make it shorted all the time.

I did all kinds of shit for that company that nobody else would do.

Now this devout, religious person who is partner wants me to lie, to put in a good review on their local whatever they got. I would in exchange for a really glowing review of me but I am not looking for work. I even stopped advertising my business. I got enough now.

I doubt the guy in Florida has my number, I might leave it that way. After all this starting a business to piss off the goniffs etc in this business and put them out of business with truth and nice reasonable repairs, I am going to lie ?

Geez.

 

[jurb...@gmail.com]

>\" true RMS \" = DC equivalent value for the *heating* effect on a resistance.

Known. but a DC meter might not be set up for that.To be, it would have to have some sort of filter and they don\'t really do that because they don\'t want the load. I think I told the guy to get a resistor and a cap, damn such uncritical values really, cana be 10K and a 47uF, or a 470 and a 10uF. It just doesn\'t matter if that meter has an input of 10 megs.

Of course TRMS might come in handy for an incandescent or some sort of heating element, but for LED it is out of the game.

I would think most LED dimmers say rated 400 watts (?) would be ready for multiple LEDs in parallel. This absolutely requires the max voltage delivered with PWM or they will not come on or dim at the same rate.

So he was trying to measure PWM on a DC scale, might work on an old style meter with a real meter, but not on this.

The first time TRMS did me any good was on TVs. Of all things, the filament winding of the power transformer opened up. I decided rather than change it, run the filament off the flyback. So I did and I wound the wire around the core and the meter read about 6.3 or so on TRMS and I connected it. ZAM it worked.

I found out that with that half sine, 70KHz wave repeating at 15.7Khz came to the right voltage at 22 volts peak to peak off the fly.

I had adventures in that. Shorted H-K ? We I got a winding for that. Panasonics seemed to be really affected by the capacitance though I tried to keep it low. So I EQed the video output circuit for it, just a cap in the emitter of one of the transistors. Short intermittent ? Fine, I just put like a 4.7 K in there to make it shorted all the time.

I did all kinds of shit for that company that nobody else would do.

Now this devout, religious person who is partner wants me to lie, to put in a good review on their local whatever they got. I would in exchange for a really glowing review of me but I am not looking for work. I even stopped advertising my business. I got enough now.

I doubt the guy in Florida has my number, I might leave it that way. After all this starting a business to piss off the goniffs etc in this business and put them out of business with truth and nice reasonable repairs, I am going to lie ?

Geez.

 

[Phil Allison]

jurb...@gmail.com wrote:
============================

This blows Phil\'s statement out the water which is rare, there is no TRMS in DC.


\" true RMS \" = DC equivalent value for the *heating* effect on a resistance.

Known. but a DC meter might not be set up for that.

** You are not paying proper attention.

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.



...... Phil

 

[jurb...@gmail.com]

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

No dispute on that, just why a DVM might not read it right.

Anyway, of the TRMS, I have noticed my average responding meter comes fairly close.

The TRMS one is a Fluke 8050A which I keep on the top shelf, it has more than enough accuracy and the LED display (which is in perfect shape HAHA) is not as easy to read as the 8000A I use as a daily driver. The 8000A has one less digit and is fast, I like it. When I need accurate then well... But then sometimes I read DC voltages with a scope. Put it on DC in most things you get like maybe 25 volts tops ? Five volts per division. Most shit you just need to know if it is there. I don\'t care from 4.96 or 5.03.

\"Hack\", say it.

 

[Phil Allison]

jurb...@gmail.com wrote:
============================

This blows Phil\'s statement out the water which is rare, there is no TRMS in DC.


\" true RMS \" = DC equivalent value for the *heating* effect on a resistance.

Known. but a DC meter might not be set up for that.

** You are not paying proper attention.

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.



...... Phil

 

[Phil Allison]

jurb...@gmail.com wrote:

=====================

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

No dispute on that, just why a DVM might not read it right.

** Cannot possibly help but do so.

Analog ones do so by virtue of meter needle inertia.

DVMs do so by virtue of a simple LP filter at the input.




...... Phil

 

[Phil Allison]

jurb...@gmail.com wrote:

=====================

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

No dispute on that, just why a DVM might not read it right.

** Cannot possibly help but do so.

Analog ones do so by virtue of meter needle inertia.

DVMs do so by virtue of a simple LP filter at the input.




...... Phil

 

[Ralph Mowery]

In article <aa517822-c73a-43ed-9ecd-565b93c49f8cn@googlegroups.com>,
pallison49@gmail.com says...

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

That really should be qualified.

The way I understnd it is that the RMS voltage produces the same ammount
of heat in a resistor as a DC voltage will.

However RMS voltage could be a high peak value that will damage solid
state devices. The meter could show 5 volts, peaks could be 50 volts.

Again DC meters could read many different values depending on the meter
and wave form.

 

[Phil Allison]

Ralph Mowery wrote:
===================

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.



That really should be qualified.

** No need exists.

The way I understnd it is that the RMS voltage produces the same ammount
of heat in a resistor as a DC voltage will.

However RMS voltage could be a high peak value that will damage solid
state devices. The meter could show 5 volts, peaks could be 50 volts.

Again DC meters could read many different values depending on the meter
and wave form.

** What I wrote was accurate.

Strange how so many are baffled by such simple stuff.




....... Phil

 

[Phil Allison]

Ralph Mowery wrote:
===================

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.



That really should be qualified.

** No need exists.

The way I understnd it is that the RMS voltage produces the same ammount
of heat in a resistor as a DC voltage will.

However RMS voltage could be a high peak value that will damage solid
state devices. The meter could show 5 volts, peaks could be 50 volts.

Again DC meters could read many different values depending on the meter
and wave form.

** What I wrote was accurate.

Strange how so many are baffled by such simple stuff.




....... Phil

 

[Ron D.]

let\'s say the following:

TRMS meters generally have AC and AC+DC modes, but usually your interested in the AC portion.
The TRMS voltage of a waveform will have the same heating value of a DC voltage set to the TRMS value.

AC meters have a frequency response. They also might be limited by the crest factor of the waveform.
There were thermal AC TRMS meters at one time.

Non TRMS meters are what you might call. Average reading, TRMS responding.
What does that mean? Take line voltage of 120 V 60 Hz sine wave. It flips the voltages below zero (i.e. precision full-wave rectify and it averages. Throws it into a capacitance filter. The result is the average value.
The meter then multiplies that average value by a constant so it reads the RMS value of the hypothetical sine wave.

The meter basically assumes it\'s being fed a sine wave, averages whatever it gets and multiplies by some k.
if you feed it a 60 Hz sine wave, you will get out the RMS value of the sine wave.

We talk about average, but the average of a typical sine wave is zero. it\'s really the average of the absolute value.of the waveform.

 

[Ron D.]

let\'s say the following:

TRMS meters generally have AC and AC+DC modes, but usually your interested in the AC portion.
The TRMS voltage of a waveform will have the same heating value of a DC voltage set to the TRMS value.

AC meters have a frequency response. They also might be limited by the crest factor of the waveform.
There were thermal AC TRMS meters at one time.

Non TRMS meters are what you might call. Average reading, TRMS responding.
What does that mean? Take line voltage of 120 V 60 Hz sine wave. It flips the voltages below zero (i.e. precision full-wave rectify and it averages. Throws it into a capacitance filter. The result is the average value.
The meter then multiplies that average value by a constant so it reads the RMS value of the hypothetical sine wave.

The meter basically assumes it\'s being fed a sine wave, averages whatever it gets and multiplies by some k.
if you feed it a 60 Hz sine wave, you will get out the RMS value of the sine wave.

We talk about average, but the average of a typical sine wave is zero. it\'s really the average of the absolute value.of the waveform.

 

[Phil Allison]

Ron D. wrote:
=============

let\'s say the following:

TRMS meters generally have AC and AC+DC modes, but usually your interested in the AC portion.

** Not true.

The reason for needing a true RMS value is to predict heating in a resistance or maybe a fuse .
So you cannot omit the DC component.


> AC meters have a frequency response.

** But DC ones do not and so are all the same.

We talk about average, but the average of a typical sine wave is zero.

** Correct.

Standard AC meters show the \"average *rectified* value \" scaled up by 11% to the RMS for a sine wave.


...... Phil

 

[Phil Allison]

Ron D. wrote:
=============

let\'s say the following:

TRMS meters generally have AC and AC+DC modes, but usually your interested in the AC portion.

** Not true.

The reason for needing a true RMS value is to predict heating in a resistance or maybe a fuse .
So you cannot omit the DC component.


> AC meters have a frequency response.

** But DC ones do not and so are all the same.

We talk about average, but the average of a typical sine wave is zero.

** Correct.

Standard AC meters show the \"average *rectified* value \" scaled up by 11% to the RMS for a sine wave.


...... Phil

 

[whit3rd]

On Friday, April 9, 2021 at 12:19:10 AM UTC-7, palli...@gmail.com wrote:

jurb...@gmail.com wrote:
============================

This blows Phil\'s statement out the water which is rare, there is no TRMS in DC.


\" true RMS \" = DC equivalent value for the *heating* effect on a resistance.

Known. but a DC meter might not be set up for that.
** You are not paying proper attention.

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

The voltage, though, for an LED lighting system is NOT
proportional to current; it\'s the current average that makes
the light output bright or dim. Neither average DC nor RMS
are suitable measures unless it\'s on a CURRENT scale rather than voltage.

 

[whit3rd]

On Friday, April 9, 2021 at 12:19:10 AM UTC-7, palli...@gmail.com wrote:

jurb...@gmail.com wrote:
============================

This blows Phil\'s statement out the water which is rare, there is no TRMS in DC.


\" true RMS \" = DC equivalent value for the *heating* effect on a resistance.

Known. but a DC meter might not be set up for that.
** You are not paying proper attention.

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

The voltage, though, for an LED lighting system is NOT
proportional to current; it\'s the current average that makes
the light output bright or dim. Neither average DC nor RMS
are suitable measures unless it\'s on a CURRENT scale rather than voltage.

 

[Phil Allison]

whit3rd wrote:
================

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

The voltage, though, for an LED lighting system is NOT
proportional to current; it\'s the current average that makes
the light output bright or dim. Neither average DC nor RMS
are suitable measures unless it\'s on a CURRENT scale rather than voltage.

** As previously posted *here* by me - the *power* delivered by a DC source is:
I average x DC voltage.

A moving coil DC meter or regular DMM will show you both.

Do the math any way you like.




....... Phil

 

[Phil Allison]

whit3rd wrote:
================

DC voltage and true RMS voltage are equivalent.
DC meters read the average, DC value of a wave.

The voltage, though, for an LED lighting system is NOT
proportional to current; it\'s the current average that makes
the light output bright or dim. Neither average DC nor RMS
are suitable measures unless it\'s on a CURRENT scale rather than voltage.

** As previously posted *here* by me - the *power* delivered by a DC source is:
I average x DC voltage.

A moving coil DC meter or regular DMM will show you both.

Do the math any way you like.




....... Phil

 

[Ron D.]

> TRMS meters generally have AC and AC+DC modes, but usually your interested in the AC portion.

** Not true.

The reason for needing a true RMS value is to predict heating in a resistance or maybe a fuse .
So you cannot omit the DC component.

===
I\'ll bite. 99% of what I did using an AC meter was measuring power supply ripple and abcense/presence of house AC or 24 VAC systems.

When I designed an I-V converter so we could measure the outut of a UV arc lamp source, that had to be TRMS.

We had lots of phase angle fired AC controllers (before I was hired) operating into variacs to drive 40V tantalum heaters (200-300W). They either worked, had a short inside the vacuum system or blew the semiconductor fuse. I then made sure they SCR;s were 25A, added the current limit option and an extra 3AG fuse. Life got better.

New or upgraded systems went with 1200W DC power supplies. 30V 40A or so. We would have liked a power meter and a programmable temperature controller. The other controllers were obsolete. They had no temperature display and had a proprietary dual SCR unit. Newer replacements would use standard process signals like 4-20 mA 0-5, or 0-10V
That allowed us to reduce panel size and not have a \"stupid panel\" that read ersatz AC voltage and ersatz AC current and had a temperature display. At one point in the earlier system, Power was important. A three-phase power meter was adapted to do the power of two low voltage single phase heaters at the cost of about $1000.00 USD. There were 7 heaters in a typical system. Sometimes wired wierdly.

In a custom system (prior to the IBM PC) that I was involved in, we did it the right way. The heaters could be controlled by voltage, current, temperature or power. The uncontrolled variable became a limit. I implemented an energy calculator and stability creiteria and recipies. The energy calculator could detect a shorted thermocouple onheat up or a misplaced on, The spreadsheet programs were not invented yet.

 

[Ron D.]

> TRMS meters generally have AC and AC+DC modes, but usually your interested in the AC portion.

** Not true.

The reason for needing a true RMS value is to predict heating in a resistance or maybe a fuse .
So you cannot omit the DC component.

===
I\'ll bite. 99% of what I did using an AC meter was measuring power supply ripple and abcense/presence of house AC or 24 VAC systems.

When I designed an I-V converter so we could measure the outut of a UV arc lamp source, that had to be TRMS.

We had lots of phase angle fired AC controllers (before I was hired) operating into variacs to drive 40V tantalum heaters (200-300W). They either worked, had a short inside the vacuum system or blew the semiconductor fuse. I then made sure they SCR;s were 25A, added the current limit option and an extra 3AG fuse. Life got better.

New or upgraded systems went with 1200W DC power supplies. 30V 40A or so. We would have liked a power meter and a programmable temperature controller. The other controllers were obsolete. They had no temperature display and had a proprietary dual SCR unit. Newer replacements would use standard process signals like 4-20 mA 0-5, or 0-10V
That allowed us to reduce panel size and not have a \"stupid panel\" that read ersatz AC voltage and ersatz AC current and had a temperature display. At one point in the earlier system, Power was important. A three-phase power meter was adapted to do the power of two low voltage single phase heaters at the cost of about $1000.00 USD. There were 7 heaters in a typical system. Sometimes wired wierdly.

In a custom system (prior to the IBM PC) that I was involved in, we did it the right way. The heaters could be controlled by voltage, current, temperature or power. The uncontrolled variable became a limit. I implemented an energy calculator and stability creiteria and recipies. The energy calculator could detect a shorted thermocouple onheat up or a misplaced on, The spreadsheet programs were not invented yet.