[ULSK]

Dear Sir

Door bells in my house fails in short time. So, I gave supply through 5W bulb and the bell ring is weak. I want to drop the electricity by less than 3W but there are no bulbs less than 5W. How can I drop electricity by 2W or 3W?

Thanks/ULSK

[hkstroud]

Door bells in my house fails in short time

Please explain what you mean by that. Do you mean the chimes fail? If so, what is the voltage of the chimes and what is the voltage of the transformer?

[ULSK]

Yes, my door bell fails in two - three months. Our power supply is 230V. The bell has very thin coil. I want to reduce the direct supply of 230v goes to the bell. When I use a 5W bulb, the bell rings only once and then it does not work for some time.(it is a Ding-Dong bell) I want to reduce the voltage goes to the bell using a bulb or something. (LED bulbs does not work here as there is a circuit.). Please help me to expand the life of the bell.Tks/ULSk

Yes sir, my door bell fails very soon.( two three months only). I want to reduce the power supply of 230V to the bell as it has very thin coils. 5W bulb or LED (as it has a circuit) do not work here. I have to use something that works with less than 5W to reduce the direct power supply to the bell. Bell may be 15V.
Tks/ULSK

[hkstroud]

First you must be located in EU or UK. I have to assume that things are done the same way there as here in the US. That is, a step down transformer is used to reduce the voltage to a low voltage circuit.
You are making an assumption that the chimes are failing because of to high a voltage, which is incorrect. You imply that you have replace the chime multiple times. I assume that you have also replace the transformer. That alone eliminates the possibility that the chimes or the transformers are at fault. Transformers are not that sensitive, such that slightly high voltage would cause a problem. Neither is the solenoid of the chime. Furthermore the behavior that you describe does not indicate a defective transformer or incorrect voltage.
The light bulb you are using acts as a resistor which is serving to restrict the current flow. True there is a slight voltage drop, but so small as to insufficient. It is the restricted or reduce current flow that is making the chime sound weak.
I have to assume that the bulb in connected in a series in the low voltage circuit.

With all that said, your problem is not with the chime or the transformer but with either the button or the low voltage wiring. When you press the button the low voltage circuit is completed and the solenoid core is pulled down, striking the lower chime bar (the Ding). When the button is released, the spring around the solenoid pulls the solenoid core up striking the upper chime bar (the Dong).

If for some reason, such as a sticking button or a short in the low voltage wiring, the circuit is not broken the core will not be released and you get the Ding only.

the bell rings only once and then it does not work for some time

That implies that the transformer has an over load or over temperature feature that is breaking the high voltage circuit. Also implies that once the current on the low voltage is interrupted (transformer high voltage current interrupted due to over heating) the low voltage circuit returns to it original state until the next time the button is pressed.

If the chime is a simple, single Ding Dong, type about the only thing that could be at fault is the button. If the chime is type the produces multiple sounds, Ding,Dong,Ding Dong there will be a small motor that is making multiple contacts and the could be something incorrect with wiring connections.

Placing the light bulb in the circuit will only cause the lowered sound. Because it also acts as a resistor, it may (or may not) reduce the current flow to an extent that the transformer does not over heat and trip off.
I suggest you find the fault and correct the problem rather than try to work around it.