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Circuit that gives a proportional output

Posted: Mon May 08, 2023 5:34 pm
by ALAN/ALAN D
Hello Gents

Looking for a circuit that connects to an A.C. Current transformer that gives a proportional output voltage for current flow. In one direction only.
Just want to make use of any power that would be flowing into the grid.

Re: Circuit that gives a proportional output

Posted: Mon May 08, 2023 7:34 pm
by sharpener
I think you need to use the voltage as well in order to get the phase relationship and hence determine the direction of the power flow. So my immersion heater diverter circuit has an analogue multiplier, the product of the voltage and current it produces is a 100Hz sinewave. This also has a DC component which is proportional to the power flow, and the sign of it indicates the direction.

If you don't need anything so precise then you could chop the current signal from the CT with a square wave derived by clippng the voltage waveform, using FETs or a CMOS analogue switch IC as the multiplier element. If you then smooth the output with a capacitor you will get a voltage proportional to the AC current, and with the correct sign.

EDIT see also this thread https://camelot-forum.co.uk/phpBB3/view ... =11&t=2145 and this product https://www.eco-eye.com/product-monitor ... escription mentioned in it.

Re: Circuit that gives a proportional output

Posted: Mon May 15, 2023 5:59 pm
by sharpener
@ALAN/ALAN D If you didn't like that idea then there are lots of other measurement techniques discussed here and here. It would be good to know how you are getting on!

Re: Circuit that gives a proportional output

Posted: Mon May 15, 2023 7:25 pm
by ALAN/ALAN D
Hello.

Not had much time to play recently.
Had big lightning strike. Took out.
Alarm system. Every house door / window was hard wired.
Sky dish / box.
phone system.
Two big T.V. s
Battery balancing controller caught fire.
Turbine inverter.
All outside lights / shed power supplies
Immersion diverter had proper bang.

Have ordered an Arduino to replace the hard wired alarm. Dont want to go down WiFi / motion detector route. My alarm in 20 years had never false triggered before the Bang. Will look into the arduino dump controller.

Many thanks for the Update.

Regards Alan
sharpener wrote: Mon May 15, 2023 5:59 pm @ALAN/ALAN D If you didn't like that idea then there are lots of other measurement techniques discussed here and here. It would be good to know how you are getting on!

Re: Circuit that gives a proportional output

Posted: Mon May 15, 2023 7:45 pm
by nowty
Ouch, that’s the second one on here with a lightning strike taking lots of electrical gear out in about a year. Seems more risky than having home batteries. :?

Re: Circuit that gives a proportional output

Posted: Mon May 15, 2023 8:46 pm
by sharpener
Blimey! The radio silence makes sense now. Hope you get it sorted.

Re: Circuit that gives a proportional output

Posted: Sat May 20, 2023 12:48 pm
by MoSTiE

Re: Circuit that gives a proportional output

Posted: Sat May 20, 2023 1:35 pm
by Fintray
MoSTiE wrote: Sat May 20, 2023 12:48 pm this?

https://mk2pvrouter.co.uk/
I've had one of these, made from a kit, for years, it has worked faultlessly and you can alter the Arduino sketch to change parameters if you require.