Call for AC Adapters


I’ve had a good 230V pure-sine inverter for awhile now, and have used it to determine phase shift at 50Hz for quite a few CTs. After the initial round of testing, I found that both the popular VTs and CTs increased phase lead by a similar amount when going from 60Hz to 50Hz. My conclusion relative to phase shift at that time, and still is, that since IoTaWatt corrects for net phase difference, it’s better to just leave the 60Hz factors. There are some mismatch scenarios where it may be better to have two sets of phase corrections, but that is for another day.

I bring this up because I’ve taken a closer look at voltage calibration, and that also seems to be affected by frequency. It’s not a big deal, and IoTaWatt allows users to fine tune their voltage calibration, but the old calibration determined at 240V 60Hz was a little high at 20.69. I’ve changed it to 20.51, which is about a 0.8% difference. Users who have not calibrated their UK adapters might want to change their units to the new value.

Following through on this topic, many folks have benefited from this project, and if you are inclined to give back, I’d like to get samples of the various AC adapters being used, especially in the 230V countries, so I can add them to the tables with tested calibration and phase correction. I don’t even have the Euro and Australian models sold by OEM, yet they are in the tables with WAGs. There is also a popular model local to Australia that I would like to add in.

So if you are inclined to contribute to the project, consider sending me one of these international AC reference transformers. You can PM me with the model you have, and if I don’t have one, I’ll reply with the USA address to send it to.

Thanks to all for your support.


Hi Bob, I think the AU VT model you refer to is

Jaycar are 1 of 2 remaining retail electronics retailers in AU and consequently charge for the privilege. AC-AC adapters are getting rare. If you don’t have one of these, I’ll see if I can source one for you.

If anyone in AU is reading this, they have a special on a discontinued model for $10 as 1/11/18.



Thanks Tony,
That’s a pricey item. If you score one, PM me and I’ll give you my address.


My thoughts exactly - I should have checked the Altronics site (other local retailer) - About $18 there but they don’t have a store within easy access and it wouldn’t be hard to spend $10 in fuel for the trip. Your nemesis (ROTFL) :sweat_smile::sweat_smile: Pete/@BlueTardis is running one of the Jaycar ones.

The problem with the Chinese sites is you become a real scrooge as you see an Arduino Uno on Jaycar for $30 knowing full well it can be had on Banggood (or DX or any other CH site) for $5- and therefore object to a 600% mark up.



Bob are you in the UK?
Im heading to London soon and could bring some adapters if you have not had any sent yet.

PM me if interested.