Hi NP,

i am fine thanks.

Ok, i think i get the picture now 

I have some pot cores, but not that small, so have to look for one in my junkbox or improvise.
Rest of the parts should be no problem.

I will try to follow your line of measurements and calculations and hopefully reach similar results.


Be well,   regards Itsu

Quote from: nul-points on December 02, 2018, 06:14:21 PM

(NB.  all values measured using a True RMS meter and confirmed in order of magnitude using a 'scope)

feedback current:  1.18mA (True RMS)
feedback LED load:  approx 2.6V * 1.18mA = 3mW approx

main LED branch current:  6.5mA (True RMS)
main LED branch load:  4.15V * 6.5mA = 26.98mW

voltage across electrolytic//main LEDs is 2.7V DC
main LED load:  2.7V * 6.5mA = 17.55 mW

switching cct load:  26.98 - 17.55 = 9.43mW

total LED load:  17.55 + 3 = 20.55mW

total power load:  20.55 + 9.43 = 29.98mW

supply current:  5.4mA (True RMS)
total power supply:  4.15 * 5.4mA = 22.41mW

Efficiency  n  =  (total load / supply)  =  (29.98 / 22.41) = 134%

results shown are instanteous power, mW (these are proportional to the energy being converted, mWh)

Hi nul-points. I tried to fairly evaluate what you have described above, but right away see the following issues:
Most true RMS meters or regular DVM's are not spec'd for use to anywhere near 130 kHz, although a few may
possibly be spec'd for use at that high of frequency. What true RMS meter were you using (make and model #)?
Do the specs for that meter indicate it can be used to measure AC currents up to at least 130 kHz?

Your terms and calculations such as 'main LED branch load', 'main LED load', 'switching cct load', 'total LED load' just aren't
making much sense to me. You would have to clarify those terms and explain or show exactly how and where you are making
those measurements if you want people to be clear about the measurements you are describing. When measuring
power in AC circuits, the phase angle between the voltage and current is very important. When you are talking about
AC circuits with pulse or spikey waveforms, power measurement can be a lot a trickier. At any rate, you can't just throw
a DVM or true RMS DVM in at different points in AC circuits to measure current and ignore phase angles.

Also, above you said "results shown are instanteous power, mW", but you can't calculate efficiency based on instantaneous power,
and you can't measure instantaneous power if you are using a true RMS meter to measure current. To calculate efficiency,
you must measure/calculate average output power and average input power. So what you said about 'instantaneous power,' really doesn't
appear to make any sense.

Not trying to be difficult at all. Just some honest feedback on what was presented. I am trying to be as nice about it as I can, but I
know from experience that honest feedback will more often either be ignored or attacked rather than being fairly considered.
My comments are directed to anyone in general who cares about really trying to understand how things are really performing
in circuits such as this. IMO, an experimenter must be willing to examine and question all assumptions being made and check all
measurements over many times with the frame of mind of what might I being doing wrong here or overlooking here, and even then
chances are that a person could still be overlooking one or more things that could be throwing their measurements/calculations off,
if they think they are measuring OU. I have seen it many times over. Unless your circuit is a self-runner, it is highly recommended
to ask for feedback from other people with experience in this area to point out any issues they might see. You must also be willing to
clearly explain or show exactly how you are making your measurements. If a person doesn't approach this sort of experimentation with
this type of mind set, then in my opinion they have most likely lost before they have even started. That might possibly sound harsh to newbies,
but long experience does prove this out. AC circuits with complex waveforms such as pulse waveforms, etc. really can be quite tricky to evaluate
(unless you can make it into a self-runner that is).

hi Void


yes, i see what you're saying, point taken - i'm obviously much more confused these days than i thought i was 

 author=Void link=topic=16384.msg527698#msg527698 date=1543920638]

QuoteNot trying to be difficult at all. Just some honest feedback on what was presented. I am trying to be as nice about it as I can, but I
know from experience that honest feedback will more often either be ignored or attacked rather than being fairly considered.
My comments are directed to anyone in general who cares about really trying to understand how things are really performing
in circuits such as this. IMO, an experimenter must be willing to examine and question all assumptions being made and check all
measurements over many times with the frame of mind of what might I being doing wrong here or overlooking here, and even then
chances are that a person could still be overlooking one or more things that could be throwing their measurements/calculations off,
if they think they are measuring OU. I have seen it many times over. Unless your circuit is a self-runner, it is highly recommended
to ask for feedback from other people with experience in this area to point out any issues they might see. You must also be willing to
clearly explain or show exactly how you are making your measurements. If a person doesn't approach this sort of experimentation with
this type of mind set, then in my opinion they have most likely lost before they have even started. That might possibly sound harsh to newbies,
but long experience does prove this out. AC circuits with complex waveforms such as pulse waveforms, etc. really can be quite tricky to evaluate
(unless you can make it into a self-runner that is).

So very very true Void

Quote from: nul-points on December 04, 2018, 06:34:50 AM
hi Void
yes, i see what you're saying, point taken - i'm obviously much more confused these days than i thought i was 

Well, not saying it is all necessarily incorrect, but was just pointing out
some likely problem areas and areas that would need clarification which I noticed.
Thanks for sharing here however.

Quote from: tinman on December 04, 2018, 06:35:13 AM
author=Void link=topic=16384.msg527698#msg527698 date=1543920638]
So very very true Void

Yes, I have tripped myself up on various occasions in the past in my own experimenting.
It is easy enough to overlook things when trying to evaluate circuit performance in these types of circuits.
Can happen to anyone for sure.