Using an AC Transformer to power my Doorbell: I dont get it, please help!


my 2 years old doorbell only runs for a week before it needs a recharge, probably because its cold outside. So lets use a transformer i thought.

What I have:

  • a pushbutton next to the doorbell
  • an electromagnetic bell (rather old)
  • a doorbell transformer: 8V 6.6VA (can be rewired to 12V 10VA)
    All of that is connected in sequence.

First I read the support pages: It tells me I need a 8-24V transformer with MAX 40VA and a 25Ohms 50 Watts resistor. So I have questions:

1.) What does MAX 40VA mean? My 6.6VA is less but since 40 VA is the MAX its fine? That makes no sense, a power supply cannot have to many watts only to many volts. So I need an actual 40VA transformer as a minimum? On Jeff Bezos rather large shopping site, close to 100% of all doorbell transformer have less than 20VA and the others are DC! Also I can charge my phones tablets and all usb devices with 5 Watts, why on earth would the doorbell need 8 times as much? I dont get it, what transformer do I need and where to buy it?

2.) I am supposed to install a resistor that heats up my wall from the inside from now unto all eternity? Why is that, a resistor in that case would lower the voltage slightly so its slightly less than 8 to 24V now… what does that achieve? Why not simply tell me what transformer is needed without a resistor?

3.) What is supposed to happen when I wired it correctly? When I simply connect the doorbell instead of the pushbutton the electormagnetic bell rings permanently, so I take that out and bridge the wires where the bell was. Now the Doobell Ring light is lit dimly (much less then when ringing or blinking normaly) Is that whats supposed to happen? Leave the battery in or not? I dont wanna test the bell for long since when it really needs 40VA it will fry my transformer. Every other device I own has a badge that tells me what power supply it needs, why not this bell?

I really feel let down by the explanation on how to install this doorbell, the support page does not even say if I have to leave the battery inside when using a transformer…

Still hoping to get this resolved and kind regards,


Hi @Zottel. Can you please confirm which model of Doorbell you have? I read through your post, but I didn’t see it mentioned there and that information is important as you want to make sure you’re looking at the correct installation instructions for the right Doorbell. You can find the Doorbells’ model name on the original packaging or on the back of the Doorbell itself.

As for the power requirements, I think there is some confusion here. The transformer that is required is an 8-24V transformer with a maximum of 40VA. This is not to be confused with a minimum power requirement, the maximum means it cannot be more than 40VA or it may cause damage to the Doorbell.

Regarding the resistor, I would again need to know which model of Doorbell you have so I can provide you with the correct information as to whether or not a resistor is needed when wiring your Doorbell to an existing doorbell circuit. It’s also important to note that wiring the Doorbell does not replace the battery, it simply provides a small percentage of trickle charge to the battery over time. The cold weather will still impact the battery, however, having it wired may help keep the battery topped off a bit longer between charges.

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thanks a lot for your answer!

The Package reads: RING Video Doorbell 2

Ok so I leave the Battery inside and the transformer provides only a trickle charge. So my 8V AC 6.6VA 50Hz should be enough.

If the 40VA is indeed a maximum that would mean that and the resistor shall prevent the doorbell from using to little power which might lead to confusing behaviour of my power supply?

So if I simply connect the stuff without any resistor my voltmeter shows arround 9V at the doorbell, does that mean I am fine?



PS: Maybe you should rephrase “max 40VA” to “ratet 40VA or less”. Since if my power supply is labeled 40VA that means it provides 40 VA maximum… and any power supply labeled 40VA or more will suffice that requirement, which is the exact opposite of what you actually mean^^

@Zottel Thanks for the additional information and feedback. You do not need a resistor when you are wiring the Doorbell to an existing doorbell and transformer circuit. You can find the installation instructions in our Help Center Article here. The only configuration that requires a resistor for the Video Doorbell 2 is if you are wiring it directly to a transformer without any existing doorbell wires. If you already have. a doorbell in your home, you do not need to install a resistor. You can find a list of which chime kits are compatible with the Video Doorbell 2 here as well.


No, if I do that my existing bell just rings permanently, so I needed to take that out of the circuit and shorten the wires over it.

Basically now I do have only a transformer a very long wire and the RING device.



@Caitlyn_Ring ok I did it! :slight_smile:

I found out the the permanent ringing only occurs when I install the Doorbell without the battery. So I wired up all devices in sequence with the battery and it seems to work now.

I still think you should insert much more information into the relevant support pages:
The following things belong there (imho)

  • The Doorbells ring led is lit dimly when everything is wired correctly.
  • The battery has to stay inside the device and shall be at 100%.
  • The transformer should be described better: example “any 50 or 60Hz AC transformer that provides 8V to 24V and is rated between 5VA and 40VA will suffice” The word “maximum” is misleading because the 40VA already is a maximum so you are describing the “maximum maximum VA” and you imply one of those "maximum"s and write down the other, but which one was not clear to me.
  • You should at least hint at the reason for the resistor and the 40VA maximum, that always helps understanding stuff.
  • Providing the “minimal maximum VA rating” of the transformer will also be helpful because that is what everyone expects when a transformer is described.
  • The power consumtion of the doorbell should also be mentioned. You can call it a “trickle charge” or you simpy state it in hard numbers like "the doorbell will consume 50mW " or so .

I have to mention that I read mostly the german RING support pages because that is what google gives me here. And there are mutiple of them. Not every information is issing on all of them.

Thanks for your help everything runs smoothly now.



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