To be deleted

[tinman]

firstly, apologies for the long gap in posting results here - i've had health issues


i've greatly appreciated the positive and interesting exchange of ideas and results with some good friends who i met here on OU.com - you know who you are!


this is likely to be my last posting on OU (for a number of reasons, not just health) and i wanted to share some results which have followed on from my previous experiments with charge-switching and feedback


i have attempted to 'distil' all that i've observed and learnt from my previous solid-state experiments

as in my orevious experiments, the switching circuit shown below operates at higher than audio frequencies (approx 130 kHz here), in 2 half-cycles a) & b):

a) the transistor switches on, its collector current illuminates the output LED(s) and also stores energy in the coil field and electrolytic cap; when the coil saturates then the transistor turns off;  enough energy remains in the electrolytic cap to supply the output LED(s) until the next cycle (the cap voltage is DC with minimal ripple)

b) current supplied from the energy stored in the collapsing coil-field and the electrolytic cap is fed back to the battery (while the transistor is off) via the feedback LED - IFF the feedback LED is illuminated then the battery is receiving charge in this half-cycle (in this case, equivalent to approximately one-fifth of the output current)

(over the last few years i've tested a LOT of exotic transformer designs, solenoidal/'partnered'/(multi)/toroidal - i don't think that there is anything unusual about the transformer here - approx 1cm^3 volume of ferrite, solenoidal wound, almost completely enclosed by the ferrite;  the wire is 2x45x0.45cm diam. insulated copper, 5:5 turns)

(Fig.1 below, Schematic)


for these tests, the battery is an LIR providing 4.15V;  supply current is 5.4mA

pk voltage of feedback pulse across feedback LED + battery is approx 7V;  pulse width approx 1.5 us

(Fig 2. below, Voltage pulse across Feedback LED)


so-called 'conventional' current flows OUT of the positive terminal of the battery in half-cycle a) and INTO that terminal in half-cycle b)

voltage across 1ohm Current Sensing Resistor in +ve supply line shows approx same peak magnitude current flows, into and out of the battery, matching the 20% duty cycle for the respective average current flows

(Fig 3. below,  bidirectional Voltage across 1ohm CSR in +ve supply line)


(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)


*** Edited to add...***


Feeding back the flyback energy, plus some stored in the electrolytic cap, has taken the whole device OU - more work is being achieved for less supply because energy is being 'recycled' back into the battery.  energy is conserved - but work isn't.


if the feedback is removed, the supply current increases; it becomes the only current path, however it is lower than the load current with feedback - less work is achieved for a higher supply level

Where are your CVRs in the schematic?
Surly you are not using a current probe at these low power levels?


Brad

[nul-points]

hi Brad, how are ye?   nice to meet you too


"voltage across 1ohm Current Sensing Resistor in +ve supply line shows approx same peak magnitude current flows, into and out of the battery, matching the 20% duty cycle for the respective average current flows

(Fig 3. below,  bidirectional Voltage across 1ohm CSR in +ve supply line)

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


[edited to show context]

[itsu]

Hi NP,

sorry to hear about your problems, i hope they change for the better soon.

Your "Efficiency  n  =  (total load / supply)  =  (29.98 / 22.41) = 134%"  warrants a further investigation.

Could you be more specific about the transformer though?

You mention:
approx 1cm^3 volume of ferrite, solenoidal wound, almost completely enclosed by the ferrite;  the wire is 2x45x0.45cm diam.
insulated copper, 5:5 turns).


I cannot picture this in my mind, so could you perhaps show a picture?
The 5:5 and 2x45x0.45cm  (i guess you mean mm) is not clear to me (2x 5 turns, or 2x 45 turns, ontop of each other
or next to each other, insulated copper = magnet wire?).

Thanks,   regards Itsu

[nul-points]

hi itsu, good to 'see' you again, i hope you are well

thanks, my motivation and attention to detail are just 2 of the things affected, as you may sense from my lack of posting, and also thinking that 0.45cm could possibly be correct as a wire diameter fitting inside 1cm^3 volume of ferrite - hah!

...i tried so hard to make sure that i reported all the details correctly, LOL


yes, the excess power value took me by surprise, too - but the circuit is so simple, with only 2 main current paths between supply, so that it was more obvious that there was something unusual happening

previous circuits which had LED loads and also stored some energy in a 2nd battery showed energy could be stored and reused but this is an interesting development to achieve with just the 1 supply battery


ok, the transformer...

yes, i should have described 2 equal lengths of 0.45mm magnet wire, cut from 1 piece 45cm long, wound as 5 turns each - i guess they could be wound on as bifilar, but i wound 1 turn of say primary, then 1 turn of secondary, then 2nd turn of primary, then 2nd turn of secondary, etc

i didnt have a fully enclosed ferrite 'pot' of 2 halves, so i improvised, i'll try to attach a photo of something equivalent** - the total volume of ferrite is approx 1cm^3  just enough to enclose the windings inside a thin shell of ferrite

(**my xfr is small, dark ferrite taped up with black tape - so i don't think it will photo well)

[Edit: corrected winding details;  added photo to show comparative size of transformer 'pot core', black rectangular object, centre of proto-board, approx 20x10x5mm, some wire is exposed at each end, topologically similar to a hollow torus containing 2 interleaved solenoidal windings, similar to bifilar wound.  poor quality photo using phone - sorry!]


i hope this helps!

thanks for reading, good luck with your experiments

[doktorsvet]

Found a picture of the OS on the Internet.
I wound 5 sections of 10 + 5 turns in each