Running LED from Mains power

[John Fields]

On Wed, 22 Jul 2009 09:18:14 +1000, David Eather <eather@tpg.com.au>
wrote:

Rich Grise wrote:
On Tue, 21 Jul 2009 09:01:28 +1000, Phil Allison wrote:
"David Eather = Utter FUCKWIT
Rich Grise wrote:
Wall warts can be surprisingly cheap - I've seen them for a dollar
at thrift stores and liquidators, and I've even rescued a few from
dumpsters, i.e., free! ;-)

Umm, are those $1 wall warts energy authority approved.
** Ever seen a wall- wart on sale anywhere that was not ?

The way they are made is what makes them safe - not the presence of some
stupid logo.

It doesn't make much sense to avoid using an unapproved capacitor by
replacing it with an unapproved transformer.
** Not when an "un-approved" isolation transformer is totally safe to use
and an "approved' capacitor will easily kill you cos it provides no
isolation.

Uh, Phil, thanks for the factual info, but is it really necessary to
yell and scream and throw insults at everybody?

Please grow up or get some anger management therapy.

Thanks,
Rich


I don't mind at all - Phil is in my kill file, but he does raise an
issue that could/should be clarified.

I made the assumption that whoever was assembling this device was smart
enough not to splat themselves across the 230volts and also smart enough
to put the device in a case so that users won't be killed either. If
that assumption is incorrect then the person has NO business touching
the mains.

In what I can see of Phil's comment the only point of sticking I have is
that no-one has any idea at all if an "un-approved isolation
transformer is totally safe" and it is very unlikely to ever be the case.

---
What you've missed, and what Phil's point was, if I may take the liberty
to make it from another viewpoint, was that the secondary of a
transformer provides galvanic isolation from the mains which a capacitor
cannot.

JF

 

[David Eather]

John Fields wrote:

On Wed, 22 Jul 2009 09:18:14 +1000, David Eather <eather@tpg.com.au
wrote:

Rich Grise wrote:
On Tue, 21 Jul 2009 09:01:28 +1000, Phil Allison wrote:
"David Eather = Utter FUCKWIT
Rich Grise wrote:
Wall warts can be surprisingly cheap - I've seen them for a dollar
at thrift stores and liquidators, and I've even rescued a few from
dumpsters, i.e., free! ;-)

Umm, are those $1 wall warts energy authority approved.
** Ever seen a wall- wart on sale anywhere that was not ?

The way they are made is what makes them safe - not the presence of some
stupid logo.

It doesn't make much sense to avoid using an unapproved capacitor by
replacing it with an unapproved transformer.
** Not when an "un-approved" isolation transformer is totally safe to use
and an "approved' capacitor will easily kill you cos it provides no
isolation.
Uh, Phil, thanks for the factual info, but is it really necessary to
yell and scream and throw insults at everybody?

Please grow up or get some anger management therapy.

Thanks,
Rich

I don't mind at all - Phil is in my kill file, but he does raise an
issue that could/should be clarified.

I made the assumption that whoever was assembling this device was smart
enough not to splat themselves across the 230volts and also smart enough
to put the device in a case so that users won't be killed either. If
that assumption is incorrect then the person has NO business touching
the mains.

In what I can see of Phil's comment the only point of sticking I have is
that no-one has any idea at all if an "un-approved isolation
transformer is totally safe" and it is very unlikely to ever be the case.

---
What you've missed, and what Phil's point was, if I may take the liberty
to make it from another viewpoint, was that the secondary of a
transformer provides galvanic isolation from the mains which a capacitor
cannot.

JF

I understand Phil's view point, I just don't agree with it.

It (a non-approved transformer) might provide isolation, or it might
not, or it might provide isolation for a while and then not, or instead
it might overheat and burst into flames.

This is exactly the same situation with a DC rated cap - It provides a
feeling of safety that may not be justified and is an accident waiting
to happen.

Considering how Phil slammed the guy who suggested the non-mains rated
cap. (and it was Phil that said the cap. should be X1 or X2 rated) I
suspect his change in stance is simply to cause an argument.

 

[Phil Allison]

"David Eather is a LIAR "

John Fields wrote:
---
What you've missed, and what Phil's point was, if I may take the liberty
to make it from another viewpoint, was that the secondary of a
transformer provides galvanic isolation from the mains which a capacitor
cannot.

JF

I understand Phil's view point, I just don't agree with it.

It (a non-approved transformer) might provide isolation,

** Non approved wall warts (aka plug-paks in Aussie ) do NOT EXIST !!

They are figment of this RAVING LUNATIC'S imagination.

This is exactly the same situation with a DC rated cap

** Total red herring to the point in question.

Cos caps provide no safety isolation from the AC supply at all.

Considering how Phil slammed the guy who suggested the non-mains rated
cap.

** The X1 or X2 mains rating is only about the cap surviving across the AC
supply.

NOTHING to do with the electrocution hazard which is INHERENT in the
circuit arrangement in question.

The use of a "wall wart " tranny is a very safe alternative.

You STUPID, LYING PIECE OF SHIT !!




...... Phil

 

[Don Klipstein]

In <ZLKdneCLR9XmT_nXnZ2dnUVZ_sGdnZ2d@supernews.com>, David Eather wrote:

Rich Grise wrote:
On Sun, 19 Jul 2009 06:15:49 -0700, JIMMIE wrote:

transients from the motor. My solution was to run the LED from a small
6.3 volt transformer bridge diode and limiting resistor. Its been two
years now and no more failures. Such an indicator could be easily
fashioned from a small wall-wart power supply.

Wall warts can be surprisingly cheap - I've seen them for a dollar
at thrift stores and liquidators, and I've even rescued a few from
dumpsters, i.e., free! ;-)

Umm, are those $1 wall warts energy authority approved. It doesn't make
much sense to avoid using an unapproved capacitor by replacing it with
an unapproved transformer.

My experience in USA is that cheap wallwarts (surplus, used) are UL
listed as "Class II Power Supply", same as new ones.

- Don Klipstein (don@misty.com)

 

[David Eather]

Don Klipstein wrote:

In <ZLKdneCLR9XmT_nXnZ2dnUVZ_sGdnZ2d@supernews.com>, David Eather wrote:
Rich Grise wrote:
On Sun, 19 Jul 2009 06:15:49 -0700, JIMMIE wrote:

transients from the motor. My solution was to run the LED from a small
6.3 volt transformer bridge diode and limiting resistor. Its been two
years now and no more failures. Such an indicator could be easily
fashioned from a small wall-wart power supply.

Wall warts can be surprisingly cheap - I've seen them for a dollar
at thrift stores and liquidators, and I've even rescued a few from
dumpsters, i.e., free! ;-)

Umm, are those $1 wall warts energy authority approved. It doesn't make
much sense to avoid using an unapproved capacitor by replacing it with
an unapproved transformer.

My experience in USA is that cheap wallwarts (surplus, used) are UL
listed as "Class II Power Supply", same as new ones.

- Don Klipstein (don@misty.com)

UL? In that case I would have no trouble/objection in using them.

My experience is that every now and then someone gets greedy and imports
the cheapest product they can get, and then when no one reputable will
buy them they dump them through bargain shops.

 

[JK]

http://www.turbokeu.com/myprojects/acled.htm


** The 230 volt version is dangerously bad design.

C1 is not rated for use with continuous, high AC voltage and will soon
fail
short and destroy the rest of the circuit.

You are giving razor blades for babies to play with

...... Phil

Well, I was very suspicious when the guy in electronics store gave me WIMA
MKS 630VDC capacitor and he said it's OK
when I asked for the AC rated one. I went to the manufacturer web page and
indeed, it was rated 630 VDC and 400 VAC.
But I haven't seen the X2 mark on it so I'm not sure what they really mean
by their 400VAC rating.


--
-jk-

 

[Phil Allison]

"JK"

Phil Allison

http://www.turbokeu.com/myprojects/acled.htm


** The 230 volt version is dangerously bad design.

C1 is not rated for use with continuous, high AC voltage and will soon
fail
short and destroy the rest of the circuit.

You are giving razor blades for babies to play with


Well, I was very suspicious when the guy in electronics store gave me WIMA
MKS 630VDC capacitor and he said it's OK
when I asked for the AC rated one. I went to the manufacturer web page and
indeed, it was rated 630 VDC and 400 VAC.
But I haven't seen the X2 mark on it so I'm not sure what they really mean
by their 400VAC rating.

**FYI:

A cap needs to be labelled with " X1 " or " X2 " to qualify as AC mains
voltage, continuously rated.

Such caps are internally quite different to standard, DC rated film caps.

HOWEVER:

Many film cap makers mischievously apply AC voltage ratings to all their DC
rated caps.

( Egs 100V poly cap = 63V AC and 400V poly cap = 200V AC etc. )

These ratings are supplied without any defined meaning !!!!!!!!!!!!!

Beware, continuous application of AC voltages above 150V rms will destroy
standard poly caps.

FYI:

Class X1 and X2 film caps are made with dual windings ( therefore two caps
in series) or are dual di-electric paper/film types impregnated with oil or
wax under vacuum and so free of all air inclusions.



..... Phil

 

[JK]

Dana Sun, 09 Aug 2009 13:24:13 +0200, Phil Allison <phil_a@tpg.com.au>
napisao/napisala je:

Many film cap makers mischievously apply AC voltage ratings to all their
DC
rated caps.

( Egs 100V poly cap = 63V AC and 400V poly cap = 200V AC etc. )

These ratings are supplied without any defined meaning !!!!!!!!!!!!!

Beware, continuous application of AC voltages above 150V rms will
destroy
standard poly caps.

.... Phil

Thanks for the info.
I would also point out that on some of schematics about AC driven LEDs on
the internet they say
that any rectifier diode from 4001... or even 1n4148 is suitable for the
rectifier bridge.
They do not consider diode reverse breakdown voltage.
--
-jk-

 

[Phil Allison]

"JK"

Thanks for the info.
I would also point out that on some of schematics about AC driven LEDs on
the internet they say
that any rectifier diode from 4001... or even 1n4148 is suitable for the
rectifier bridge.
They do not consider diode reverse breakdown voltage.

** No need to do that - as the bridge is never subjected to a large voltage.

Think about it.



..... Phil

 

[JK]

Dana Sun, 09 Aug 2009 14:12:56 +0200, Phil Allison <phil_a@tpg.com.au>
napisao/napisala je:

They do not consider diode reverse breakdown voltage.
** No need to do that - as the bridge is never subjected to a large
voltage.
Think about it.
.... Phil


I had in mind LED strings, 20 or more LEDs.

--
-jk-

 

[Phil Allison]

"JK"
Phil Allison

They do not consider diode reverse breakdown voltage.
** No need to do that - as the bridge is never subjected to a large
voltage.

Think about it.



I had in mind LED strings, 20 or more LEDs.

** Still not even close to 100 volts - dickhead.



...... Phil

 

[Hammy]

On Sun, 09 Aug 2009 14:00:10 +0200, JK <N@o.n.e> wrote:

Dana Sun, 09 Aug 2009 13:24:13 +0200, Phil Allison <phil_a@tpg.com.au
napisao/napisala je:

Many film cap makers mischievously apply AC voltage ratings to all their
DC
rated caps.

( Egs 100V poly cap = 63V AC and 400V poly cap = 200V AC etc. )

These ratings are supplied without any defined meaning !!!!!!!!!!!!!

Beware, continuous application of AC voltages above 150V rms will
destroy
standard poly caps.

.... Phil

Thanks for the info.
I would also point out that on some of schematics about AC driven LEDs on
the internet they say
that any rectifier diode from 4001... or even 1n4148 is suitable for the
rectifier bridge.
They do not consider diode reverse breakdown voltage.

read through this.

http://uk.geocities.com/ronj_1217/tless.html

 

[JK]

Dana Mon, 10 Aug 2009 03:00:53 +0200, Phil Allison <phil_a@tpg.com.au>
napisao/napisala je:

"JK"
Phil Allison


They do not consider diode reverse breakdown voltage.
** No need to do that - as the bridge is never subjected to a large
voltage.

Think about it.

I had in mind LED strings, 20 or more LEDs.

** Still not even close to 100 volts - dickhead.
Phil

I am sorry to upset you so I did a microcap simulation to see where I went
wrong. It's a basic bridge circuit
powered from 220VAC with a 100uF filter cap and 10kOhm load and it shows
that diodes in the bridge
have over 160V peak inverse voltage. With disconnected load it goes to
maximum 340V peak.
1n4001 has reverse breakdown rating of 50 volts,
so as you say if you have two in series in the bridge it's 100V, but still
too low.




--
-jk-

 

[Phil Allison]

"JK"

They do not consider diode reverse breakdown voltage.
** No need to do that - as the bridge is never subjected to a large
voltage.

Think about it.

I had in mind LED strings, 20 or more LEDs.

** Still not even close to 100 volts - dickhead.
Phil

I am sorry to upset you so I did a microcap simulation to see where I went
wrong. It's a basic bridge circuit
powered from 220VAC with a 100uF filter cap and 10kOhm load and it shows
that diodes in the bridge ...

** Massive case of moving the goal posts.

Go drop dead - fuckhead.



...... Phil

 

[JK]

Dana Wed, 12 Aug 2009 15:37:03 +0200, Phil Allison <phil_a@tpg.com.au>
napisao/napisala je:

I am sorry to upset you so I did a microcap simulation to see where I
went
wrong. It's a basic bridge circuit
powered from 220VAC with a 100uF filter cap and 10kOhm load and it shows
that diodes in the bridge ...


** Massive case of moving the goal posts.

Go drop dead - fuckhead.
..... Phil

I don't think it is, because when the load, whatever it is, is
disconnected,
as for example when you do PWM with mosfet,full reverse voltage is applied
on
the bridge which is not disconnected from mains. I think that post fits
well
into the subject. Anyway, ...Phil, thanks for the information on X2
capacitors,
but don't bother to reply anymore.


--
-jk-

 

[Phil Allison]

"Jerkoff Kunt"


** Massive case of moving the goal posts.

Go drop dead - fuckhead.



...... Phil

 

[Michael A. Terrell]

JK wrote:

I am sorry to upset you so I did a microcap simulation to see where I went
wrong. It's a basic bridge circuit
powered from 220VAC with a 100uF filter cap and 10kOhm load and it shows
that diodes in the bridge
have over 160V peak inverse voltage. With disconnected load it goes to
maximum 340V peak.
1n4001 has reverse breakdown rating of 50 volts,
so as you say if you have two in series in the bridge it's 100V, but still
too low.

Phil is mentally ill. Ignore him, like most people do.


--
You can't have a sense of humor, if you have no sense!

 

[Ashish Dembla]

use a 56k quarter watt resistor in series and it should work perfectly.
Ashish


JK wrote:

Dana Sun, 09 Aug 2009 14:12:56 +0200, Phil Allison <phil_a@tpg.com.au
napisao/napisala je:


They do not consider diode reverse breakdown voltage.
** No need to do that - as the bridge is never subjected to a large
voltage.
Think about it.
.... Phil


I had in mind LED strings, 20 or more LEDs.

 

[Eeyore]

Tom Biasi wrote:

"Charlie+" <charlie@xxx.net> wrote in message
news1ol55l50rrt1usq529janj5vht8ipp6dv@4ax.com...
Reading the thread on battery power with interest...
Is there a minimal and cheap junk box circuit that anyone can recommend
for
running a (blue 25 to 40mA) LED at near its maximum output but from mains
power - 230V ac in my case?
Thanks

Problems with AC mains is the voltage varies a lot and spikes are common.
The drop needed is large compared to the LED voltage.
Take a look at this circuit: http://www.turbokeu.com/myprojects/acled.htm

The efficiency will be doubled by using a bridge rectifier feeding the
LED instead of a single inverse diode across the LED, e.g. 4 x 1N4148.

I am also suspicious about the low value of the series resistor which is
there to limit peak current at switch-on. Examine Ipk from the LED data
sheet and calaculate accordingly.

Graham

 

[Roger Dewhurst]

Eeyore wrote:

Tom Biasi wrote:
"Charlie+" <charlie@xxx.net> wrote in message
news1ol55l50rrt1usq529janj5vht8ipp6dv@4ax.com...
Reading the thread on battery power with interest...
Is there a minimal and cheap junk box circuit that anyone can
recommend for
running a (blue 25 to 40mA) LED at near its maximum output but from
mains
power - 230V ac in my case?
Thanks

Problems with AC mains is the voltage varies a lot and spikes are common.
The drop needed is large compared to the LED voltage.
Take a look at this circuit: http://www.turbokeu.com/myprojects/acled.htm

The efficiency will be doubled by using a bridge rectifier feeding the
LED instead of a single inverse diode across the LED, e.g. 4 x 1N4148.

I am also suspicious about the low value of the series resistor which is
there to limit peak current at switch-on. Examine Ipk from the LED data
sheet and calaculate accordingly.

Graham

What about two small capacitors in the input lines to the bridge
rectifier, a fat capacitor across the bridge output to stabilize the
voltage and a string of diodes to reduce any excess voltage to the LED?
The two input capacitors provide impedance rather than resistance.

Would that work?

R