KA4EP Torch (kacher torch)

[MarkE]

I grabbed a couple 555 timer chips, and configured them for a short duty cycle variable frequency...
a very short duty cycle draws a lot of power (ends up using a low resistance on the charge side); will probably add a hex-inverter in after the drive, and use a large duty cycle instead... and I expect the issue to remain after this change.
When the duty cycle is long enough to (close) the transistor and get a good current through the coil, at the shutoff side, there is a HUGE amount of noise introduced.  I added the resistor & capacitor in series with another capacitor to ground (supposedly adjustable, but I'm just breadboarding so it's all adjustable)  like in akula lantern 4... (attached)
is it the transistor I've used that makes this unavoidable?  Is there a way to make it less noisy?
I added a diode between the inductor (to collector of transistor) because apparently the transistor used by akula must have such a character, because the feedback is progressively lower, and with every transistor I have if the collector is lower than the base, then it conducts... that's how I meter them to see they are still good... so there must be a internal blocking diode for the signal to remain.... or an omitted part...


but anyway; about the noise?

If you have transistors turning inductors on and off rapidly, then it becomes important to have a controlled place for the inductor current to keep flowing.  This affects both circuit design and layout.  If you have a bunch of stray inductance in the switched path, then the inductor current being switched will have to overcome that stray inductance, and it will with a huge dv/dt.

[Madebymonkeys]

If you have transistors turning inductors on and off rapidly, then it becomes important to have a controlled place for the inductor current to keep flowing.  This affects both circuit design and layout.  If you have a bunch of stray inductance in the switched path, then the inductor current being switched will have to overcome that stray inductance, and it will with a huge dv/dt.

Hi,

I asked earlier but, what is the purpose of the cct?

Cct 1 (the Russian sch):
Is the energy passed into the storage cap at 'start' apparently less that what goes into the load?

Cct 2 (joule thief?):
This looks like a std step up dcdc converter (joule thief?), something which can be achieved much more efficiently with a $0.25 converter off the shelf...plus a small $0.25 inductor.

Have I got the wrong end of the stick here?
Making our own inductors, transformers and oscillators is fun (and a great learning exercise) but whats the underlying purpose of the Akula 'thing'?

[d3x0r]

If you have transistors turning inductors on and off rapidly, then it becomes important to have a controlled place for the inductor current to keep flowing.  This affects both circuit design and layout.  If you have a bunch of stray inductance in the switched path, then the inductor current being switched will have to overcome that stray inductance, and it will with a huge dv/dt.

Okay I did just run into a note about a driver board for these color LEDs where the signal switch time is 1.5us; and it was said that the matching resistors should be mounted as close to the board as possible.  I do still have original long leads on the parts... and maybe that's enough inductance to cause an issue.  I did see that the internals of the 555 are better for driving a signal than a tl494 since it's both a pull up(pnp) and pull down(npn) system instead of a single transistor...


But specifically I had removed the excess parts, so it's just the primary coil from power to the collector (with a diode between the inductor and collector but that didn't change anything).  I started with simply the 555 pin 3(output) to the base of a transistor, the coil and ground.  Not a lot of complexity.  The secondary is open (not conducting).  THis was a 3 inch long jumper wire though... but when brought to ground, the 555 should be an NPN conducting to ground for the base... which means the only current really being stopped is against the collector.... I dunno I guess I have some extra inductance on the ground side, could add some filter caps near the drive transistor

[d3x0r]

Hi,I asked earlier but, what is the purpose of the cct?Cct 1 (the Russian sch):Is the energy passed into the storage cap at 'start' apparently less that what goes into the load?Cct 2 (joule thief?):This looks like a std step up dcdc converter (joule thief?), something which can be achieved much more efficiently with a $0.25 converter off the shelf...plus a small $0.25 inductor.Have I got the wrong end of the stick here?Making our own inductors, transformers and oscillators is fun (and a great learning exercise) but whats the underlying purpose of the Akula 'thing'?

(edit2: cct1: yes, but why.  and cct2: just part of the cct1 that's self oscillating and simpler part count...)

To break a simple supposed long running device into its parts to see why it might work. (some claim it's a supercap rebranded to look like a 2200uf cap; but I have caps that have 3 lines in a triange which they claimed was 'telltale signs' it was a supercap.  It means nothing.  I have some that have 6 (kinda like >-+-< .. a split X with a | in the middle) )
given a breakdown of the remainder of the circuit as applied to a self pulser (laser saber teslamaker.com flashlight variation) with additional paths for feedback to keep the high side high and the low side low, although it helped was not an end-all solution)


The next area to investigate is Melnichenko supposed effect https://www.youtube.com/watch?v=TT9ynJ2_6Ng


all 3 images, yellow is gate, blue is collector.
image 1 : base goes high, collector to 0, gate goes high, collector goes high, nothing special, this is a pot core, no gap.  This is also how I've seen every air core work.
image 2 : akula's device during build demonstrating... (flyback core) base goes high, collector goes low, collector pulses high, and results in a voltage below 0.
image 3 : my own flyback core, base goes high, collector goes low, and after a short time gets a kickback pulse (actually many in quick succession), but never in a voltage below 0.


Should be getting my bobbins and E cores today to try some variations in genuine melnichenko style... just was trying to find a better pulser, the TL494 idles at 10ma draw... the 555 timer can already beat this easily...


---
3rd time's the charm... first time image was too big for upload, second time it thought I already submitted this message... so here goes 3


Edit: yes, it's kinda fun, yes it's definatly a learning XP, but a canned part is also already known to not work continuously on 2200uF power... not saying one can't be built, but they don't yet build them.

[Madebymonkeys]

(edit2: cct1: yes, but why.  and cct2: just part of the cct1 that's self oscillating and simpler part count...)

To break a simple supposed long running device into its parts to see why it might work. (some claim it's a supercap rebranded to look like a 2200uf cap; but I have caps that have 3 lines in a triange which they claimed was 'telltale signs' it was a supercap.  It means nothing.  I have some that have 6 (kinda like >-+-< .. a split X with a | in the middle) )
given a breakdown of the remainder of the circuit as applied to a self pulser (laser saber teslamaker.com flashlight variation) with additional paths for feedback to keep the high side high and the low side low, although it helped was not an end-all solution)


The next area to investigate is Melnichenko supposed effect https://www.youtube.com/watch?v=TT9ynJ2_6Ng


all 3 images, yellow is gate, blue is collector.
image 1 : base goes high, collector to 0, gate goes high, collector goes high, nothing special, this is a pot core, no gap.  This is also how I've seen every air core work.
image 2 : akula's device during build demonstrating... (flyback core) base goes high, collector goes low, collector pulses high, and results in a voltage below 0.
image 3 : my own flyback core, base goes high, collector goes low, and after a short time gets a kickback pulse (actually many in quick succession), but never in a voltage below 0.


Should be getting my bobbins and E cores today to try some variations in genuine melnichenko style... just was trying to find a better pulser, the TL494 idles at 10ma draw... the 555 timer can already beat this easily...


---
3rd time's the charm... first time image was too big for upload, second time it thought I already submitted this message... so here goes 3


Edit: yes, it's kinda fun, yes it's definatly a learning XP, but a canned part is also already known to not work continuously on 2200uF power... not saying one can't be built, but they don't yet build them.

Got it. Do you have any measurements for power in vs power out?
LEDs are a nice visual load but they illuminate down to a very low current - a resistor is a great load (especially if connected low side) as you can measure V with a scope across it and calculate power.

Also, I guarantee that you would be able to find an oscillator which operates with a lower Iq than a homebrew  The TL494 and 555 aren't suited to high efficiency converter applications at all. Choose a chip from this century from the likes of ON Semiconductor, Torex or Linear Tech and you will see a difference in Iq of a huge amount. If you need something for simple pulses - use an inverter and a crystal (or RC).

Finally, 'gate' (along with drain and source) is typically used with field effect transistors, base (along with collector and emitter) with BJT's - mixing two naming conventions can cause confusion to those who don't know what you 'really' mean. Please don't take this the wrong way, I really am not trying to be an ass! 

As for the supercap thing and 2200uF 'power' - a canned/packaged part can run happily on whatever (within reason!) input you provide...just depends on the load current vs time. Many packaged parts have extremely low Iq (and dropout) and will run down to voltages well below your BJT cct. The http://www.linear.com/product/LTC3108 for instance, can run as a step up converter happily down to 20mV.

If you do the math on input power vs output power then you will realise that there is no OU. It may be close...but no cigar. To get closer to a theoretical 100% efficiency you should embrace some off the shelf semi's - do one cct with and one without, see the difference with your own eyes.