Design Con 2015
Breaking News
Comments
grouts
User Rank
Rookie
re: Simple circuit measures RMS value of AC power line
grouts   11/9/2012 5:22:08 PM
NO RATINGS
The above circuit and thesis is reasonably OK. A couple of things not included in the above engineering are: - loss of course in the line/circuitry leading to the above measuring circuitry, including to the two resistors. - The thermo properties of the two resistors being heated by the signal-under-test and the DC signal. You have to, of course, also include the TRANSIENT thermo properties of both (I never did trust DC, including the wiring to/from the power supply.) By the way, I believe your above circuit, including it basic premise, is covered by a patent taken out by Norm Dillman while at HP. Myself, I used similar circuit approaches as this to provide thermal biasing stability on the many class B power amplifiers I designed for GE Audio Products back in the 60's. But you have a nice circuit as well as a nice paper describing it and your engineering. --Steve Grout

hithesh
User Rank
Rookie
re: Simple circuit measures RMS value of AC power line
hithesh   11/10/2012 10:47:06 AM
NO RATINGS
I actually thought this article would explain how you get RMS output from AC. Nothing useful in this article.



Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

DIY Practical Joke Project Idea
Max Maxfield
8 comments
I just received a rather interesting email from a member of the EETimes community who prefers to remain anonymous. This message was as follows:

Jolt Judges and Andrew Binstock

Jolt Awards: The Best Books
Jolt Judges and Andrew Binstock
1 Comment
As we do every year, Dr. Dobb's recognizes the best books of the last 12 months via the Jolt Awards -- our cycle of product awards given out every two months in each of six categories. No ...

Engineering Investigations

Air Conditioner Falls From Window, Still Works
Engineering Investigations
2 comments
It's autumn in New England. The leaves are turning to red, orange, and gold, my roses are in their second bloom, and it's time to remove the air conditioner from the window. On September ...

David Blaza

The Other Tesla
David Blaza
5 comments
I find myself going to Kickstarter and Indiegogo on a regular basis these days because they have become real innovation marketplaces. As far as I'm concerned, this is where a lot of cool ...