power meter

It depends. If you're happy with a sealed box, resistors work just fine. Actually, thinking about it, I suppose not so well for 3 phase.

It may not be necessary to use CT's if you use a dedicated power measurement IC such as Analog Devices ADE7756AN

A project describing a single phase power meter was described in Silicon Chip in July/August 2004

Since you appear to be in the UK this kit would work there since we use a similar power supply (we use 240Vac 50Hz MEN). You will only need to change the appliance output socket to suit the UK plug type.

A kit comprising all necessary components including a pre-programmed PIC is available from Australia for AUD 110.00 (UKP45.50). Even with postage you won't build one cheaper.

Ross, are you aware you posted this with "do-not-archive" - which means the record of this thread will be damaged?

I thought the opto-isolator mutiplier used in this was rather clever.

This optocoupler won't give you any accuracy. There are couplers intended for linear operation with a double output, one of which could be used for linearisation, but a small current transformer will be cheaper and more stable probably.

I found this link that explains how to test the active power manually.

Its a straight forward test, I think accuracy will depending on the voltmeters and the series resisitor value.

Harshana

David Collier wrote:

voltage measuring device :

Does anyone happen to have a copy of Woodward's original article pp.102-103 of the October 14, 1994 Electronic Design?

Best regards, Spehro Pefhany

"mires" a écrit dans le message de news: snipped-for-privacy@z34g2000cwc.googlegroups.com...

Not wierdless, hopeless.

SNIP

Win,

I turned it off at a time when I was engaging in a verbal tet-a-tete argument with another poster some time back. I figured that any self respecting archive didn't need all the sh.t one sees in posts such as this. I also figured that if other posters not using X-no archive were interested in what I was posting on a particular subject, and which they thought deserved being archived, then they would do as you have done and included my words of wisdom in a response so that it did become archived.

I have now turned it back on again anyway...

Well I'm happy to pot this section, if it works for me.

I suppose I could use a 0R01 1/W resistor and some big tracks.

If it's that easy, why doesn't everyone do it that way? Presence of mains voltages on the PCB I suppose.

David

my hero. Thanks - I looked in DigiKey, but obviously looked straight past it.

David

Basically, yes. And that you've got to make sure all buttons/... are isolated. And that it can make it a bit more difficult to develop, if it's not isolated.

I think I've seen it Web somewhere Speff, or something extremely similar.... full circuit description, etc.