So where / when are you measuring 10v when it started at 24v ?


The link here says the resistor is to replace the 'load' a true Bell (or other ringer) would present.
https://support.ring.com/hc/en-gb/articles/205180710-How-to-Connect-Your-Ring-Video-Doorbell-Directly-to-a-Low-Voltage-Transformer-Without-a-Pre-existing-Doorbell


So accordingly if the resistor is in place, I would not expect the voltage after it (at the bell push) to be 24v amy more..

The article also suggests that a trabsformer as low as 8v ac can be used (though again it does not say how much current)

end of the day, the resistor appears to be there to trickle (and not over-) charge the battery, so I expect it to work fine with any voltage over the battery value (3v ?)

Almost certainly can help but only with quite a bit more info about exactly what you have in front of you -

1 )firstly  which model of doorbell, they have a made a few over the years

2 ) is the 24 V and 10v measured on load  or off load, and between where and where in the circuit

3) is this a real real transformer of the kind with  an iron laminations and copper wire producing mains frequency AC  on the output, or an electronic substitute with either a DC output or a high frequency AC ?.

4) Do you have a bit more info about this resistor mod - is there a link you can include to a diagram, web page, instructions you can show?

Thanks for replies 

The 10v was measured on the output offload

 it's a ring doorbell 2 where's it takes small ammount dc but to be hardwired it needs between 16 - 24v? Haven't tried it yet 


so I fitted in a British general module transformer and ran a bell wire directly to the ring doorbell, which I can't connect direct. I read that I have to add this wirewound resistor for it to work? I will upload pictures but I will get details of the bell shortly

this model ?  if so then wiring diags  are    here?    

It needs to be a proper 50Hz AC transformer, not an electronic one. have you got a link to the BG model, we can check that. ?

  Also you only need the resistor if you do not actually have a real bell as part of your doorbell circuit, as it takes the place of the bell between power supply and contacts and limits the current that passes when the button is pushed.

If it is not present it looks like the power supply is shorted out when the button is pressed.

here

Hello, 

this is the transformer I used 
https://www.screwfix.com/p/british-general-8-24v-8-va-bell-transformer-module/8707p

there was no existing bell wire. I ran a new one and I've brought an wirewound resistor it 25 ohms 50 watt. I have to connect that to one leg after the transformer it says

OK the data for that specific transformer is  here  Oddly that data sheet says it generates DC;  but the diagram on the case implies  the secondary is indeed a proper 50Hz type of device, and there are 'taps' or terminals part way along the secondary coil, so you can either take 24V from the two extreme ends, or 12V from one end and the terminal in the middle,  and as there is a further tapping point from approx 1/3 of the  way along one of the 12V halves, you also have the option of 8V or 4V instead, not useful for your case but it is actually quite a versatile little unit.


Please use your meter to verify the output is AC while we complain to BG that either their data sheet is incorrect or their device labelling...  like they care.


So, assuming that it is the right thing, and  I presume then that you are seeing 10V across the '8V' section of the output winding, as these voltages are all only truly correct supplying the nominal full load, and can be expected to rise a bit off-load, and fall a bit on-load (20-25% variation between on and off load is quite common on small transformers like this - a normal door bell does not give a hoot, and thinner wire keeps the size down).


I suggest you look at the other  pairs of output terminals on the tranny, and select the ends to get  nearer to 24 (or maybe use one end and the middle  '12V' one if it is really more like 16V - 17V, and the '24V setting is a more like 30 ),  then run a pair of wires to the resistor, which  needs to be in-line with one of  the leads, as per the last diagram I linked to in my previous  post.

Where is the resistor going to be installed?


For that matter where is the bell transformer going to be installed.


Andy Betteridge

Hello thanks for the advice guys. I added the wirewound resistor to one leg and connected it to the 24v output and read perfectly fine this time on the door bell wires and works fine now. Thank you for your time. springhy ?