Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

On 8 Nov 2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

Not really, far easier to get a matching power supply.

--
Flying on Per Ardua ad Astra

WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

I doubt it!

Presumably the new door bell came with a power supply? Just graft it to the
existing wiring if you don't want to redecorate.

Tim

--
Please don't feed the trolls

Tim+ wrote:
WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

Apologies, missed this bit.

Think you'll just need to look harder. ;-)

I'd be most surprised if the transformer has been channelled into a wall.
Usually they're next to the main fuse box.

Tim

--
Please don't feed the trolls

On 8 Nov 2016 15:59, Tim+ wrote:
Tim+ wrote:
WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

Apologies, missed this bit.

Think you'll just need to look harder. ;-)

I'd be most surprised if the transformer has been channelled into a wall.
Usually they're next to the main fuse box.

Tim

But all that finding it gives you is an 18 volt DC power supply.

--
Flying on Per Ardua ad Astra

Zephirum wrote:
On 8 Nov 2016 15:59, Tim+ wrote:
Tim+ wrote:
WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

Apologies, missed this bit.

Think you'll just need to look harder. ;-)

I'd be most surprised if the transformer has been channelled into a wall.
Usually they're next to the main fuse box.

Tim

But all that finding it gives you is an 18 volt DC power supply.


Not if you rip out the old transformer and connect the new power
supply/bell transformer to the old transformer's supply and connect the
output to the existing bell wires.

Tim

--
Please don't feed the trolls

"Zephirum" wrote in message
...
On 8 Nov 2016 15:59, Tim+ wrote:
Tim+ wrote:
WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

Apologies, missed this bit.

Think you'll just need to look harder. ;-)

I'd be most surprised if the transformer has been channelled into a wall.
Usually they're next to the main fuse box.

Tim

But all that finding it gives you is an 18 volt DC power supply.

It allows him to put the new 8V transformer there
and have it use the wiring that is in the walls etc fine.

On Tuesday, 8 November 2016 15:34:37 UTC, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

A 50Hz oscillator could do it if suitably rated. Many 8v ac devices are also happy on 12v dc, so a regulator could also work.


NT

In article ,
WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

18v would be unusual for a door bell. Did you measure the voltage from the
power supply with no load? The sort used for this likely has very poor
regulation since it doesn't much matter. Real doorbells will work over a
wide range of voltage.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

If it's an electronic device it will run off DC. So if no internal
transformer, it will accept DC too. The DC will go through its internal
rectifier OK. If so a simple regulator will give you the DC voltage you
want. Exactly what that is, I'm not sure. As a nominal 8v AC supply
depends on how it is rectified etc for the final DC voltage. Can this
device be run off batteries? That would tell you what it needs, DC wise.

--
*The closest I ever got to a 4.0 in school was my blood alcohol content*

Dave Plowman London SW
To e-mail, change noise into sound.

On 08/11/2016 16:48, Dave Plowman (News) wrote:
In article ,
WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

18v would be unusual for a door bell. Did you measure the voltage from the
power supply with no load? The sort used for this likely has very poor
regulation since it doesn't much matter. Real doorbells will work over a
wide range of voltage.

I'd guess 18v with no load, nominal 12v supply but 8v and transformer
humming in protest when the solenoid is being powered continuously.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

That is an unusual requirement. Most modern stuff uses a DC switched
mode PSU (or even batteries) rather than an iron transformer and AC.

If it's an electronic device it will run off DC. So if no internal
transformer, it will accept DC too. The DC will go through its internal
rectifier OK. If so a simple regulator will give you the DC voltage you
want. Exactly what that is, I'm not sure. As a nominal 8v AC supply
depends on how it is rectified etc for the final DC voltage. Can this
device be run off batteries? That would tell you what it needs, DC wise.

You need to know how much current the new device will draw and what its
absolute maximum voltage rating is. It might be possible to put a well
heatsinked 5W 10v Zener diode in series to drop the excess voltage. eg

https://www.rapidonline.com/on-semi-...-diode-47-2302

It only has to survive a few seconds of intermittent use.

Somewhat grubby solution and it might not work if the thing draws too
much current when going ding dong or if the psu regulation is ropey.
(as seems likely from the OPs description)

--
Regards,
Martin Brown

On 08/11/16 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

You will probably find that the new bell only requires 8V AC because it
converts it internally to whatever DC voltage it requires to operate,
possibly by no more than a rectifier and smoothing circuit. You could
try connecting a 7.5V DC supply to it to see if it works (and change the
polarity if it doesn't). If it does, and you want to be bothered, you
could try one of these:
http://www.ebay.co.uk/itm/DC-4V-38V-...-/122202388683

And select the voltage output which you have checked works ok. Whatever
you do, don't connect up the 18V DC supply directly to the new bell.

--

Jeff

On Tue, 8 Nov 2016 16:50:22 +0000, Jeff Layman
wrote:

On 08/11/16 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

You will probably find that the new bell only requires 8V AC because it
converts it internally to whatever DC voltage it requires to operate,
possibly by no more than a rectifier and smoothing circuit. You could
try connecting a 7.5V DC supply to it to see if it works (and change the
polarity if it doesn't). If it does, and you want to be bothered, you
could try one of these:
http://www.ebay.co.uk/itm/DC-4V-38V-...-/122202388683

And select the voltage output which you have checked works ok. Whatever
you do, don't connect up the 18V DC supply directly to the new bell.

I agree with that, although I'd want at least three buck converters
for that price.
http://tinyurl.com/nb5l6be

Just to be certain, if the OP could tell us the make and model of his
new doorbell it would help.




--

Graham.

%Profound_observation%

On Tuesday, 8 November 2016 15:34:37 UTC, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

No.

On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

There is no /simple/ way to convert. Best buy a transformer - it seems
that 8V AC is quite a common doorbell voltage. For something that's
connected to the mains and left unattended for years, I wouldn't fiddle
about.

https://www.amazon.co.uk/Friedland-D.../dp/B00EPESM2U


Cheers
--
Syd

On 08/11/16 17:43, Syd Rumpo wrote:
On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

There is no /simple/ way to convert. Best buy a transformer - it seems
that 8V AC is quite a common doorbell voltage. For something that's
connected to the mains and left unattended for years, I wouldn't fiddle
about.

https://www.amazon.co.uk/Friedland-D.../dp/B00EPESM2U


If the power so low enough and audio amplifier fed from a 50Hz
oscillator is one way.



Cheers


--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

On 08/11/2016 17:59, The Natural Philosopher wrote:
On 08/11/16 17:43, Syd Rumpo wrote:
On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

There is no /simple/ way to convert. Best buy a transformer - it seems
that 8V AC is quite a common doorbell voltage. For something that's
connected to the mains and left unattended for years, I wouldn't fiddle
about.

https://www.amazon.co.uk/Friedland-D.../dp/B00EPESM2U



If the power so low enough and audio amplifier fed from a 50Hz
oscillator is one way.

Would you *seriously* fit that yourself rather than use a bell
transformer designed for continuous use? It's not simple, not
certified, certainly not as reliable and awkward to explain to the
insurance company when the firemen have left.


Cheers
--
Syd

On 08/11/16 18:31, Syd Rumpo wrote:
Would you *seriously* fit that yourself rather than use a bell
transformer designed for continuous use? It's not simple, not
certified, certainly not as reliable and awkward to explain to the
insurance company when the firemen have left.

GHiven that I was an audio circuit designer for may years, probably ';-)

I thught he needed AC from DC?

A 'bell transformer' only works from AC..


--
The theory of Communism may be summed up in one sentence: Abolish all
private property.

Karl Marx

On Tuesday, 8 November 2016 18:31:17 UTC, Syd Rumpo wrote:
On 08/11/2016 17:59, The Natural Philosopher wrote:
On 08/11/16 17:43, Syd Rumpo wrote:
On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

If the power so low enough and audio amplifier fed from a 50Hz
oscillator is one way.

the audio amp can be the oscillator.

Would you *seriously* fit that yourself rather than use a bell
transformer designed for continuous use?

I'd use a voltage regulator.

It's not simple,

it is

not
certified,

what's that got to do with anything?

certainly not as reliable

no less reliable than any electronics. If you're competent you can do it to mil spec.

and awkward to explain to the
insurance company when the firemen have left.

no it's not. Insurance doesn't exclude electronics, and it's trivial to make it not a fire risk.

The only thing that might need ac is some small bells that work the wacker at 50Hz.


NT

On 08/11/2016 21:25, wrote:
On Tuesday, 8 November 2016 18:31:17 UTC, Syd Rumpo wrote:
On 08/11/2016 17:59, The Natural Philosopher wrote:
On 08/11/16 17:43, Syd Rumpo wrote:
On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

If the power so low enough and audio amplifier fed from a 50Hz
oscillator is one way.

the audio amp can be the oscillator.

Would you *seriously* fit that yourself rather than use a bell
transformer designed for continuous use?

I'd use a voltage regulator.

Do you know it will work with DC?

It's not simple,

it is

not
certified,

what's that got to do with anything?

certainly not as reliable

no less reliable than any electronics. If you're competent you can do it to mil spec.

A mains transformer designed specifically for continuous use is more
reliable than a bunch of electronics. Why would you even argue the point?

and awkward to explain to the
insurance company when the firemen have left.

no it's not. Insurance doesn't exclude electronics, and it's trivial to make it not a fire risk.

The only thing that might need ac is some small bells that work the wacker at 50Hz.

And this might well be one. The Amazon reviews of a Friedland 8V AC
doorbell suggest a 'Brrrrrrrrh!' sound.

Like this, perhaps...
https://www.youtube.com/watch?v=VWwk76SEAno

Or if it's a simple electromechanical 'ding - dong' type using a
solenoid actuator then there is a difference between AC and DC
solenoids, just as AC and DC relays are different.

Wind your neck in, bellend.

Cheers
--
Syd

In article ,
Syd Rumpo wrote:
On 08/11/2016 17:59, The Natural Philosopher wrote:
On 08/11/16 17:43, Syd Rumpo wrote:
On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

There is no /simple/ way to convert. Best buy a transformer - it
seems that 8V AC is quite a common doorbell voltage. For something
that's connected to the mains and left unattended for years, I
wouldn't fiddle about.

https://www.amazon.co.uk/Friedland-D.../dp/B00EPESM2U



If the power so low enough and audio amplifier fed from a 50Hz
oscillator is one way.

Would you *seriously* fit that yourself rather than use a bell
transformer designed for continuous use?

Of course. He's a very clever electronics design engineer. I'm told. By
him. And his company went bankrupt.


It's not simple, not
certified, certainly not as reliable and awkward to explain to the
insurance company when the firemen have left.

Assuming the 18v supply can provide enough current - which is likely since
an electronic device is replacing a mechanical one (I guess) a simple
voltage regulator should do the job.


Cheers

--
*Virtual reality is its own reward *

Dave Plowman London SW
To e-mail, change noise into sound.

On 09/11/2016 00:52, Dave Plowman (News) wrote:

snip

Assuming the 18v supply can provide enough current - which is likely since
an electronic device is replacing a mechanical one (I guess) a simple
voltage regulator should do the job.

Friedland make some doorbells which will *only* work on AC. They also
make doorbells which work on 8V AC or 6V DC. The implication there is
that the bisexual ones are solenoid operated and the higher AC is needed
to overcome the coil impedance at 50Hz.

Page 62 of this...

https://www.friedland.co.uk/Document...gue%202008.pdf

Why guess? I'm sure you've come across these on old houses - the
illuminated push button with a dim under-run (for longevity) lamp which
goes out when you press the bell.

Cheers
--
Syd

Syd Rumpo wrote:
On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.

There is no /simple/ way to convert. Best buy a transformer - it seems
that 8V AC is quite a common doorbell voltage. For something that's
connected to the mains and left unattended for years, I wouldn't fiddle
about.

https://www.amazon.co.uk/Friedland-D.../dp/B00EPESM2U


Cheers

This.

Tim

--
Please don't feed the trolls

On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.



It all depends on why it needs an AC supply. If its then rectifying the
8V AC to get a 12V DC supply you may find that the first component in
the doorbell is a bridge rectifier followed by a smoothing capacitor.

If this is the arrangement you could feed in DC - and possibly the 18V
you already have. Assumptions: a bridge rectifier as the first
component and 18V is the no load voltage that possibly would drop under load

Do you have a photo of the innards of the doorbell showing any
components that may related to a power supply?



--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

"WeeBob" wrote in message
...
Hello.

I have an old wired doorbell that has an 18V DC power supply. The actually
transformer has been (I think) channelled into the wall, or underfloor
boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

It may well not care about getting DC instead of AC, it might
well just rectify that and rectifying DC will still work fine.

Not always tho, particularly with more fancy stuff like modems,
and external hard drives, they can generate a variety of voltages
from the AC and when supplied by DC can't do that.

The difference between 18V and 8V is more of a problem tho
and it isnt trivial to reduce that without using a voltage regulator
that you presumably dont know much about if you have to ask.

On 08/11/2016 15:34, WeeBob wrote:
Hello.

I have an old wired doorbell that has an 18V DC power supply. The
actually transformer has been (I think) channelled into the wall, or
underfloor boards in the attic. i.e. hard to get to.

A new fancy doorbell requires connection to a 8V AC power supply.

Is there a simple way to do this? i.e. 18V DV in, 8V AC out?

Thanks.


Some esoteric answers ... just buy the correct transformer and run in a
new piece of bell wire ... its so small you will forget its there in a
weeks time.