Lasersaber strikes again. A joule thief king ?

[Vortex1]

Greetings Conrad

I looked over the data sheet for the TVS slvscf2 part......very nice.

Regards, Vortex1

[Pirate88179]

Conrad:

http://www.digikey.com/en/articles/techzone/2013/feb/specialized-low-input-voltage-boost-converters-enhance-efficiency-in-energy-harvesting-designs

Here is a listing of some boost converters. I like the ISL9111A which will work down to .5 volt!  This article explains the advantages of each type.  This would make a great, tiny JT circuit that draws very little power and would milk just about any battery down pretty low and give light for a long time.

I came across this in my research for my next project.  If I can get some of these in a few weeks, I will keep you posted.

Bill

[4Tesla]

Conrad:

http://www.digikey.com/en/articles/techzone/2013/feb/specialized-low-input-voltage-boost-converters-enhance-efficiency-in-energy-harvesting-designs

Here is a listing of some boost converters. I like the ISL9111A which will work down to .5 volt!  This article explains the advantages of each type.  This would make a great, tiny JT circuit that draws very little power and would milk just about any battery down pretty low and give light for a long time.

I came across this in my research for my next project.  If I can get some of these in a few weeks, I will keep you posted.

Bill

Very cool IC!  This one is DIP which is easier to use.

LT1110CN8

http://www.digikey.com/product-search/en?pv183=4573&pv69=80&FV=fff40027%2Cfff8029a&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25

Can get on ebay or aliexpress.

[conradelektro]

@Pirate88179: very nice article about booster ICs.

I like the reasonable price of the following two ICs from the article:

http://at.mouser.com/ProductDetail/Microchip/MCP1623T-I-CHY/?qs=%2fha2pyFadugOTv0PoQ7miXqoZFdHi4vci3qDnRNtLN2RTlguhZ8rbYPf86xK5tKg

http://at.mouser.com/ProductDetail/Microchip/MCP1640BT-I-CHY/?qs=%2fha2pyFadugOTv0PoQ7miVsXBOvd1GmiEY8KeayLYS1fbqm7P3CYeeG3lLgCDobC


@4Tesla: the LT1110CN8 seems to be an older product, although very versatile, a bit expensive.


A DIP package is nice for tinkering, the surface mounted devices are a pain for my clumsy fingers. It helps to have these bread boards (kind of expensive) and a fluxing agent (to keep the solder from flowing over several tiny copper patches).

http://at.mouser.com/ProductDetail/SchmartBoard/204-0004-01/?qs=%2fha2pyFadugqOhGLyXU2llu%2fmMPT2OP66bN6KkSUAAEGYGE5uXFBEg%3d%3d

http://at.mouser.com/ProductDetail/Kester/952D6/?qs=sGAEpiMZZMtyU1cDF2RqUBbfted9QYcQxvK4ulH8h7Y%3d


I really like the MSP430L092  ultra-low-power microcontroller, but there are no convenient development options (no EEPROM).

http://www.ti.com/product/msp430l092

Greetings, Conrad

[conradelektro]

I got some MPSA18 transistors and could test LaserSaber's circuit as published here http://laserhacker.com/?p=410

My transformer is different and the LED is different (it is a red LED, it doe snot work with every LED, I had to try several).

My transformer is shown in this post http://www.overunity.com/14591/lasersaber-strikes-again-a-joule-thief-king/msg403065/#msg403065 where I discussed the same circuit with a 2N1304 Germanium transistor.

See also here:
http://www.overunity.com/14591/lasersaber-strikes-again-a-joule-thief-king/msg403087/#msg403087
http://www.overunity.com/14591/lasersaber-strikes-again-a-joule-thief-king/msg403109/#msg403109
http://www.overunity.com/14591/lasersaber-strikes-again-a-joule-thief-king/msg403189/#msg403189

It looks like the MPSA18 transistor works best as of low power draw.

In this latest test of LaserSaber's circuit I measured less than 0.3 µA at 9 V (less than 300 nA at 9 V).

At 3 V the power draw is lower than I can measure.

The red LED flickers (low frequency) and the light is of no use, just a theoretical experiment.

The LED was flickering dimly on a 1000 µF electrolytic cap (starting with a 9 Volt charge) for 4 hours and 30 minutes (then I terminated the test):

1000 µF  * 9 V = 0.009 As (charge at start Voltage)
-1000 µF *  2 V = 0. 0.002 As (charge at stop Voltage)
0.007 As in 16200 seconds (4 h 30 min) --> 0.007 / 16200 = 0.4 µA on average

It seems that the circuit really draws less than 0.3 µA. The circuit stops to work at around 1 Volt. The crucial element seems to be the MPSA18 transistor which allows for a very short on time.

Turning the LED around increases the frequency and raises the power draw to 0.8 µA at 9 Volt and surprisingly to 1.9 µA at 3 Volt. Very strange. I also found a white LED that works (also the flickering and the strange effect when turning the LED around).

My coil (transformer) is not optimal, I guess it should be like that:

- 1 layer of 0.4 mm wire as primary (will have about 70 to 80 turns)

- 6 layers of 0.4 mm wire as secondary (will have about 420 to 480 turns) (1:6 ratio)

- a last layer of 0.4 mm wire which I can add in series to the secondary to get a 1:7 ratio

Further tests and measurements are planned.

Greetings, Conrad