Cool joule ss/ssg

[TinMan]

Just had to come back and revisit the cool joule now that i have a 2 channel digital scope-->and glad i did.
For L1 & L2,i am useing a couple of coils from solenoids out of an old washing machine(the ones on the valves that control water flow). Both the steel sleeves have been removed so as they are air core coils/inductors. I have also removed the diode that was between the collector and LED. The new schematic is as below. I have also taken a scope shot(below)-Blue trace across emitter/base,and yellow trace across emitter/collector. I have switched to a TIP35C transistor as well. What i find interesting is-first,the transistor seems to be switching on with only 480mV on the leading pulse. But the trailing pulse has me a bit confused. How do we get the second pulse on L2 when the base voltage is still negative?

As before,i am getting a combined battery voltage rise that is now .7 volts higher than when i started. Although no longer fooled by rising voltages,it is still an interesting effect,and even more so when useing NI-CDs

[TinselKoala]

I _think_ that what you are seeing is the ringing of one of the coils when the transistor is off, going through two peaks then being "struck" again by the transistor when the base voltage reaches sufficient level. I don't have a matched pair of coils with sufficient inductance and resistance to check with my own equipment; I suppose I should wind a pair just to be sure, but that's what it looks like to me from your scopeshot.

I also don't have a TIP35C in my box. Does it do the same kind of thing with a 2n3055 or equivalent type?

[TinMan]

I _think_ that what you are seeing is the ringing of one of the coils when the transistor is off, going through two peaks then being "struck" again by the transistor when the base voltage reaches sufficient level. I don't have a matched pair of coils with sufficient inductance and resistance to check with my own equipment; I suppose I should wind a pair just to be sure, but that's what it looks like to me from your scopeshot.

I also don't have a TIP35C in my box. Does it do the same kind of thing with a 2n3055 or equivalent type?

With the 2n3055,the second peak is about 1/2 a division lower on the scope. Other than that,it is much the same.

[TinselKoala]

With the 2n3055,the second peak is about 1/2 a division lower on the scope. Other than that,it is much the same.

That makes sense. Just by inspection, it looks like that double-peak ringing is at about 40 kHz (one full cycle in 25 microseconds). So you could try a non-powered test with batteries disconnected to see if the coil-transistor resonance is in fact near 40 kHz: Loop a couple turns of wire around the L1 coil and connect that to your signal generator through a 50 ohm resistor. Hook the scope up across the coil-transistor connections. Sweep the FG's output frequency and look for the maximum voltage that you get on the scope. If it peaks at the same 40 kHz, then you've identified the source of the double-peaks as the resonant ringing of the coil-transistor combo.
I think, maybe.

I did this test on my little version with the two 1mH toroids and BC337-25 transistor and it worked perfectly to confirm that the oscillations are due to the coil-transistor combo ringing. At a much higher frequency than your version, of course!

[Slider2732]

This has to be one of my all time fave circuits and am glad you are re-testing Tinman.
Also, that TK is here and moving things along.

Recently, an original build Cool Joule ran for 3 months continually on 2x 100mAh yellow solar garden light Ni-Cd AAA's !
It was put on a table and practically forgotten about. When it stopped, a quick short across the transistor and off it would run again for several days.
Circuit used 2x 'dancing flower' 500ohm coils side by side and a superbright white LED. Transistor being a (iirc) C1815. Lumens were low, yet from knowledge of the terrible quality of the garden light batteries, it lasted well past regular discharge traits.
My new scope hasn't arrived yet, but it may well be worth trying to hook up my wobbly buttoned erratic scope to follow along.

[PhysicsProf]

 

Recently, an original build Cool Joule ran for 3 months continually on 2x 100mAh yellow solar garden light Ni-Cd AAA's !
It was put on a table and practically forgotten about. When it stopped, a quick short across the transistor and off it would run again for several days.
Circuit used 2x 'dancing flower' 500ohm coils side by side and a superbright white LED. Transistor being a (iirc) C1815. Lumens were low, yet from knowledge of the terrible quality of the garden light batteries, it lasted well past regular discharge traits.
My new scope hasn't arrived yet, but it may well be worth trying to hook up my wobbly buttoned erratic scope to follow along.

   Very intriguing, Mark!
Ps -- I checked and they say your scope has shipped, so its on its way!

[Itsu]

Hi Slider,

i put something together yesterday and toke some scope shots and made measurements, perhaps they come in handy when your new scope arrives.

Using a MJE3055 transistor, a big (10mm) blue led and some transformer windings as aircoils (191 Ohm/106mH and 185 ohm/93mH) and 2x 1.2V 750mAH NiCd batteries

Its running for 24 hours now, need to tickle the base to get it started

Yellow is the voltage across the collector to ground (emitter)
Blue   is the voltage across the base to ground
purple is the current to/from the lower nicd battery  (2mA/Div)
green  is the current through the total battery stack (1ma/Div)


So current is very low and hard to register on the scope.

Video here:   https://www.youtube.com/watch?v=iCaiNJ0Zd2Q&feature=youtu.be

Regards Itsu

[Chet K]

Scope delivery note.
I double checked on that "already Shipped" and apparently that was from the west coast USA to their
east coast shipping terminal ,where they will then be shipped to fill orders.
long story short....they'll be shipping to customers by 4/1.

[Slider2732]

Thanks for the scope updates
This circuit will be ideal as a tester for getting used to it.

Thanks for your results Itsu, always well shot useful videos. Btw, the batts appear to be 250mA, rather than 750ma ?



Say, i'm just thinking about something. The whole scopes container goes from a California port to the East coast, then they put a few on a truck for deliveries westward and presumably a couple of them end up back in California ? LOL

[Itsu]

Slider,  i just double checked,  they are 700maH:

Regards Itsu

[Slider2732]

Haha, so we were both a little out. Guess who read the charge rate on your video by mistake
Should last well at that rating if fully charged and allow for good accurate discharge graphing.

[TinselKoala]

Well, just checking in with my version. I'm using the extra diode, a BC337-25 transistor, a blue LED and 2 toroids of 1mH each, about 30 - 32 turns of #33 wire on each one. I still haven't been able to duplicate tinman's double-peaks but as you can see the collector and base waveforms are pretty similar to Itsu's, but at a higher frequency due to the lower inductance.

As I said above, I've also confirmed that this frequency is the natural ring frequency of the tank formed by L1 and the transistor (with no batteries connected). I looped a couple of turns thru the L1 toroid, connected that to the FG thru a 50 ohm resistor, connected scope across coil-transistor connections, and swept the FG until I got maximum voltage on the scope, then read frequency on the Philips counter.

[Itsu]

Ok,  i could try that, but first want to leave it running to see how long it goes.

I use the primary windings of some 220V/12V transformers now, but i started with the both secondaries (around 1 Ohm each) and the frequency then was around 300KHz and
pulling much (relative) more current, so yes, the used L's heavily determine the pulse frequency.
Also no double pulse seen here like in tinmans screenshot.

Regards Itsu