In rec.radio.amateur.boatanchors Jerry Stuckle wrote:
On 11/28/2014 7:23 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle wrote:
On 11/28/2014 5:24 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle wrote:
On 11/28/2014 4:11 PM, wrote:
In rec.radio.amateur.boatanchors Michael Black wrote:
On Fri, 28 Nov 2014, wrote:

In rec.radio.amateur.boatanchors gareth wrote:
These LED replacements for 240V mains lamps; if one were to
open them, would one find a high voltage regulator suitable for
some of our valve experiments and repairs?

As the regulators are potted in and would be difficult to remove, and
since LED's run on voltages on the order of 2-3 volts, no.

How many 3 volt valves can you name?

I think that point was that if a regulator was used to drop the line
voltage to those 3volts, it could handle high voltage input. The probably
false assumption is that the regulator would be variable from some very
high output voltage to some very low output voltage, so one could use it
for tubes by making that adjustment.

Given that manufacturers want the least cost in a product, and the
regulator in a light bulb would have no need for a variable regulator,
and that these things are made in the millions, it would be extremely
silly to assume that the regulator is anything other than a fixed
regulator for LED's and is designed to handle the load of some fixed
number of LED's.


Once again, incorrect. Have you ever heard of "dimmable LED bulbs"?
How do you dim without an adjustable regulator?

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?


For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

Yes, for LED bulbs.


Once again you show your ignorance.

Once again you are arguing for the sake of arguing.

However, the simplest way to see that the light output is controlled
by the applied voltage is to simply look at the base of a dimmable
bulb and note that there are only two connections; no third connection
for a control, just the same as all other light bulbs.


Which means nothing.

Which means there can not be a control wire for a variable regulator.

The only input a light bulb has is the input voltage.

Some are dimmable and some are not because it takes more parts to make
a dimmable bulb and the demand for them is less than that for non-dimmable
bulbs.

To specifically answer your question, you design a regulator who's output
is some precentage of the raw input as opposed to a regulator who's
output is always equal to some reference voltage.


Again, it all depends.

Nope; light bulbs run at a rated voltage which is the standard voltage
for the country in which they are sold; US light bulbs are rated for
120v, UK bulbs for whatever the voltage is over there, I think 240V.

You are just arguing for the sake of arguing.


No, I am arguing from facts - unlike you. I've been in the business of
installing lighting control (and other things) for 11 years now. We
install numerous LED control systems every year.

I forgot that you are an expert on EVERYTHING and to call into question
anything you say is the ultimate insult.

And to be yet more specific, since LED brightness is proportional to
current and resistors would waste power, the regulator would be a
current regulator with an average current output proportional to the
raw input voltage.


Then why can't you use standard incandescent dimmers with LED bulbs?

You can if the bulb is specified as dimmable; some are, and some are not
and they all use the standard two connection E26 base.


Wrong again.

Yes, right again.

Light bulbs in the US use the E26 base and some are dimmable and some are
not.

If you have doubts, go into Home Depot, Lowe's, or any place that sells
light bulbs and look.

A lot of IC regulators can't handle high voltage. If nothing else, nobody
saw the need, it was the solid state age. So dissipation issues aside,
most regulators expect at most a relatively low DC voltage input.

True for IC regulators. Hoever high voltage transistors exist these
days which makes designing a high voltage regulator pretty trivial.


Sure. But how do you handle the current requirements without some kind
of transformer?

Well, assuming you want some voltage greater than the wall plug maximum,
the need for a transformer is pretty much a given unless some sort of
voltage multiplying rectifier is sufficient for the need, which is
where the current requirement becomes relevant.

However, the subject was high voltage regulators, not where does the
raw high voltage come from.


And where do you get the current necessary to supply the LEDs in the
bulbs? A typical LED required around 3V (usually 2.7V to 3.3V,
depending on the LED)? A 9 watt LED would require 3 amps of current.
Or, if the LEDs were in series, something less. But without a
transformer, the current would still exceed that of an incandescent bulb.

None of this has anything to do with high voltage.


It has to do with the current required by the bulbs.

Which is two orders of magnitudes less than what a standard US outlet
is capable of supplying.

The standard US wall outlet is rated at 15 Amps.

A Phillips A21 75W replacement LED bulb draws 15W at 120V (0.125A)
and is dimmable.


Yes, and at 3V that would require 5 amps. At 120V that would be 600W,
not 15W.

So what is your claim here; that LED light bulbs HAVE to hae a transformer?

http://www.usa.philips.com/c-p/04667...white-dimmable

You obviously are unfamiliar with the structure of LED bulbs.

You obiously have never noticed that the base of an LED bulb is identical
to that of an incandescent, i.e. two wire E26 base, and that standard wall
outlets in the US are 15 Amps.



Which only means they can plug into a standard socket and run off of 120V.

Again you are arguing for the sake of arguing.

How long until you start with your usual ad hominems?


--
Jim Pennino