Doorbells... 18VDC in to 8VAC out?

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

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.

That's what 'stock' IC voltage regs do. DC in and out. Only need a few extra components. Something like an LM317 if you want to set the voltage. Or you could use a fixed voltage type.

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...

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

You think it's needed. IRL solenoids are very tolerant. Try working with them some time.

NT

Friedland think it's needed, or at least desired. They have been making doorbells for a very long time.

Now f*ck off and find something else you don't know about to pontificate upon.

Cheers

Yes.

The DC one has a switch operated by the solenoid, IIRC. Hence being AC/DC. Think the AC only ones vibrate at mains frequency.

IMHO it was very unusual to have a DC supply derived from mains for a bell. Despite having worked in many old houses, I've never seen one. Either a simple transformer for AC units, or batteries for DC.

So Friedland have invented the very first solenoid operated device that's fussy about its input have they? Come back when you know something about solenoids. And know why traditional doorbell transformers have at least 2 outputs and how they're used.

NT

Nowhere on p62 do I see anything that states the device must only be run at those exact voltages. Your attempts at logic are as faulty as your knowledge of electromechanical devices.

NT

Just google something like "difference between ac and dc solenoid". Maybe consider why AC and DC relays are different too.

You know a bit about electronics and think that electromechanics is trivial. Like a lot of technicians, you've too much output and not enough input.

Cheers

's fussy about its input have they? Come back when you know something about solenoids. And know why traditional doorbell transformers have at least 2 outputs and how they're used.

I know what the differences are. Inductance alters voltage rating, and ther e's avoiding armature buzzing on ac. There are also considerations re heat dissipation when activated a high percentage of the time. All these are sig nificant in some situations. None of these prevent a simple door dingdong w orking just fine on ac or dc. Nor do they alter the fact that for low duty cycle use, solenoids are very unfussy about their supply voltage.

Well, you're free to offer some valid content rather than daft ad hominem a nd foolish arguments like 'Friedland say this is the rated voltage so it mu st be exactly that.'

NT

Yuk. That would sound pretty awful. Most I have seen just relied on AC to limit the current through the solenoid if the switch stuck on.

Their design dates from the era when rectifiers were bulky and unreliable selenium based things and have never really moved on. AC also protects the solenoid from over current to some extent.

These days battery powered wireless doorbells are much less hassle and come with a variety of chimes, flashers and volume settings.

it works for some small bells.

Sure, but the old technology proves much more reliable, and you tend to not get enough volume from electronic sounders.

NT

Well there are two kinds of hassle, installation hassle and maintenance hassle.

Wireless score excellently at the first but are dire for the second (in my experience).

Wired transformer powered ones are excellent from the maintenance POV but much more hassle from the installation POV.

Battery powered wired ones fall somewhere in the middle but the cheaper ones have the huge advantage of having just one REAL ringtone and none of this MP3 recorded crap. Just my opinion of course. ;-)

Tim

But nothing like as loud as my pair of underdome bells.

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.