Power supply AC/AC and AC/DC

Hi gents,

I've set up the emonTx V2 with temperature and power measurements. All is OK except Power that is stuck to 0.

After checking on the useful OpenEnergy site, it seems AC/AC power is mandatory for power.

It also seems that the AC/DC 5V supply is still needed when the AC/AC is used. So two supply for one board!


I see in schematics that AC/AC is more like a sine wave reference than a supply.

Can I use any reference for euro plug for the AC/AC in the shop? Or what is your favorite.

Best regards,


Robert Wall's picture

Re: Power supply AC/AC and AC/DC

You do indeed need two adapters for the emonTx V2. But the AC-AC adapter is not a power supply, it is measuring the alternating line voltage. So you are correct when you say it is a voltage reference. We recommend the adapter from the shop. We know the characteristics of that one (see the report in the Building Blocks section) but we do not know how any other will perform regarding the accuracy of the voltage output (distortion, phase errors etc).

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