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Author Topic: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?  (Read 144812 times)

MileHigh

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #315 on: July 09, 2016, 11:34:35 PM »
Well, I can easily see Brad having a braingasm from TK's posting so I will get a few words in edgewise.

One of the classic weaknesses on the forums is to use the term "efficiency" without even defining what it means.  Brad is someone that does this all the time.

Take a look at a Joule Thief.   Are we talking about electrical power in vs. electrical power out efficiency like Poynt just stated?  Or are we talking about electrical power in vs. light power out like TK just stated?

What about the LED itself?  Are you doing your "burn" at the optimum efficiency point for the LED where you get the most light out per milliwatt in?

How flat or sloped is the current discharge curve across the LED when you are doing a burn?  Does this have an impact on the power in to light out efficiency?

What about the flashing frequency and duty cycle and human perception of brightness?

What about the human perception of the light level?   How do you define an "adequate" level of light output from the Joule Thief?  Is it just bright enough to be a panel indicator light?  Or do you want a practical amount of light like a small night light?  Is there a sweet spot for human perception of the light output from a Joule Thief?

How you define efficiency for a Joule Thief is a big enough question for such a little circuit.  But it is what it is.

Just saying, "Wow, that looks like an efficient Joule Thief!" is essentially meaningless if you don't qualify it.

Quote
(snip)
For instance,the schematics below.
You say !your! JT circuit(1) is the most efficient,and i say circuit 2 is more efficient
(snip)

Oh my god I must be wrong based on TK's data!  Brad is going to have a braingasm!

Why did I say that circuit #1 might be more efficient?

My line of thinking was as follows:  In circuit #1 when the LED is lit it is based on a discharge of the LED in series with the battery.  So the EMF from the battery is a "helper" to keep the LED lit.  So, it suggests to me that circuit #1 may be able to extract more energy from a nearly dead battery because it looks like it will run at lower battery voltages than circuit #2.  That will likely translate into a longer run time from the same battery.

How did I define "efficiency" for the "most efficient Joule Thief?"

The answer was the most efficient Joule Thief by my definition would be the one that has the longest run time and extracts the most possible energy from the nearly-dead battery.

I stated this to Brad multiple times but it never sank in.

Now we can go back into the holding pattern waiting for Brad's expected tsunami braingasm.

Brad:  I still would like to see your "bench smarts" measurement procedure for your supercapacitor.

minnie

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #316 on: July 09, 2016, 11:38:54 PM »



   TinselKoala , with circuit 2 you could always strike a match to see if it's
   switched on!
    Warmest regards,John.

poynt99

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #317 on: July 09, 2016, 11:54:05 PM »
Well there we have it Chet. It's a no-go.

MH and TM will just have to keep bickering at each other I guess... :P

TinselKoala

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #318 on: July 10, 2016, 12:06:41 AM »
At even lower voltage, this time from a relatively fresh #357 button cell battery instead of the power supply, the efficiency reverses, with Circuit 1 being more efficient.

At 1.4 volts:
#1 gives 35.9 lux at 41.4 mW = 867 lux/watt
#2 gives 23.9 lux at 32.3 mW = 740 lux/watt

So, as usual... both TinMan and MileHigh are right, and wrong... depending.

 ;D

TinselKoala

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #319 on: July 10, 2016, 12:20:56 AM »


   TinselKoala , with circuit 2 you could always strike a match to see if it's
   switched on!
    Warmest regards,John.

No need for that! Both circuits make the LED I'm using "blindingly bright" when viewed by eye. I'm barely able to see the difference in brightness, but the lightmeter tells the tale.

MileHigh

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #320 on: July 10, 2016, 12:24:34 AM »
No need for that! Both circuits make the LED I'm using "blindingly bright" when viewed by eye. I'm barely able to see the difference in brightness, but the lightmeter tells the tale.

Phasers on blindingly bright....

markdansie

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #321 on: July 10, 2016, 12:39:52 AM »

Take a look at a Joule Thief.   Are we talking about electrical power in vs. electrical power out efficiency like Poynt just stated?  Or are we talking about electrical power in vs. light power out like TK just stated?

What about the LED itself?  Are you doing your "burn" at the optimum efficiency point for the LED where you get the most light out per milliwatt in?



Hi MH
I had a recent experience that is very relevant to this. I was in China at a lighting manufacturer who we are having build some lighting technologies using our Hydra-Cell. I had with me a simple Dc to DC converter designed by the late Mark E , a water cell and a lux meter with 3 leds in a tube attached.
The Chinese engineers said they had designed a more efficient board according to the volts/amps in and volt/amps out. So we tested there using the water cell and the lux meter measuring light output. We measured 570 units of light. We then put in the Mark E board and measured 1270 units of light. They are still dumb founded. So measuring light output vs electrical sheds a whole ne light onto things.


The led we used has an efficiency of 180 lumens per watt in this case. It is always important to use the same led when testing and the optimum power that led has been designed for


We have also tested many variations of the Joule Thief and the closest was about 85% as efficient according to light output.
In the case I just explained the light output was what we wanted as it is being applied to a lighting product.
Many other variable can come into play.


The trick in this case was the circuit extracted the maximum energy available out of the cell by forcing it to operate at the optimum voltage we had established by power characterization testing.


I hope my experience helps to understand that there are many other variables in the equation when comparing light output to electrical output.


PS TK has some knowledge of what I am talking about


Kind Regards
Mark Dansie




TinselKoala

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #322 on: July 10, 2016, 12:44:26 AM »
Well, I can easily see Brad having a braingasm from TK's posting so I will get a few words in edgewise.

One of the classic weaknesses on the forums is to use the term "efficiency" without even defining what it means.  Brad is someone that does this all the time.

Take a look at a Joule Thief.   Are we talking about electrical power in vs. electrical power out efficiency like Poynt just stated?  Or are we talking about electrical power in vs. light power out like TK just stated?

What about the LED itself?  Are you doing your "burn" at the optimum efficiency point for the LED where you get the most light out per milliwatt in?

How flat or sloped is the current discharge curve across the LED when you are doing a burn?  Does this have an impact on the power in to light out efficiency?

What about the flashing frequency and duty cycle and human perception of brightness?

What about the human perception of the light level?   How do you define an "adequate" level of light output from the Joule Thief?  Is it just bright enough to be a panel indicator light?  Or do you want a practical amount of light like a small night light?  Is there a sweet spot for human perception of the light output from a Joule Thief?

How you define efficiency for a Joule Thief is a big enough question for such a little circuit.  But it is what it is.

Just saying, "Wow, that looks like an efficient Joule Thief!" is essentially meaningless if you don't qualify it.

Oh my god I must be wrong based on TK's data!  Brad is going to have a braingasm!

Why did I say that circuit #1 might be more efficient?

My line of thinking was as follows:  In circuit #1 when the LED is lit it is based on a discharge of the LED in series with the battery.  So the EMF from the battery is a "helper" to keep the LED lit.  So, it suggests to me that circuit #1 may be able to extract more energy from a nearly dead battery because it looks like it will run at lower battery voltages than circuit #2.  That will likely translate into a longer run time from the same battery.

How did I define "efficiency" for the "most efficient Joule Thief?"

The answer was the most efficient Joule Thief by my definition would be the one that has the longest run time and extracts the most possible energy from the nearly-dead battery.

I stated this to Brad multiple times but it never sank in.

Now we can go back into the holding pattern waiting for Brad's expected tsunami braingasm.

Brad:  I still would like to see your "bench smarts" measurement procedure for your supercapacitor.

You bring up lots of valid points wrt "efficiency" of a JT type flashing/pulsing light. There are many many variables to be considered, both in the circuit itself (like number of turns, core material, impedance of power source, etc) and in the behaviour of the LED, the lightmeter, etc. As far as I can tell this lightmeter is doing a pretty good integrating of the 9-13 kHz flashing of the LED so I mostly believe in its readings. I don't have "threshold" operation levels yet, that is I don't know the low voltage limit of the two circuits. It seems to be the case that the supply impedance affects the efficiency (my definition, Lux/watt input power) but I'll have to do more testing to see how much. (Power supply vs battery have different impedances.) Then there is the matter of the turns ratio of the inductor. Then again, the different waveforms that the oscilloscope sees on the input current measured across the 0.1 ohm CSR in the two cases may be affecting the calculations of the average input power, although I've made the computation using DMM measurements and they agree with the scope measures to within 10 percent or so.

So nobody should take my measurements as "solving" the issue or supporting either side of the argument _at this point_. At best, I am trying to establish a reasonable testing protocol that can be used to track down the effects of the various variables in the experiment.

ramset

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #323 on: July 10, 2016, 01:58:04 AM »
Poynt
Quote
Well there we have it Chet. It's a no-go.

MH and TM will just have to keep bickering at each other I guess...

end quote.

Well I commend you for your thoughtful input ,and it is quite obvious you can see a path towards this taking place
and I know itsu would be able to work hand in hand with MH to assist in the necessary bench test for dialing in his circuit.

itsu has done this "bench time" very well with Verpies and others.

However
There is definitely a high anxiety level ATM.
------------------
Compliments to Tinsel for his Input !!

we shall see??

Respectfully
Chet

tinman

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #324 on: July 10, 2016, 02:15:17 AM »
While it is very amusing to see you mates arguing back and forth, it has been a long time since anyone has actually posted any real empirical results. Some of the arguing and conjecturing (hand-waving, or maybe ****-waving   ;)   ) has to do with the Joule Thief circuits and their efficiency. So I decided to make up a test bed and do some testing.

The results so far are to be considered preliminary, but it looks like Circuit 2 is the efficiency winner, by a thin margin. It produces less brilliant light but on a lux per watt basis it wins.

I am running short on suitable toroids so I wound the inductor on a small pot-core setup. This is probably even better than using a toroid, and a heck of a lot easier to wind. Both L1 and L2 are 20 turns of #34 magnet wire.

I couldn't get my power supply to set precisely at 1.5 volts; the voltage monitor showed 1.62 volts for the tests I have run. I checked input voltage and current both with DMMs and with oscilloscope and got essentially the same results. The output ran one LumiLed super-efficent LED in my lightbox, with the ExTech LT300 lightmeter, with sensor 18 inches away from the LED. As you can see from the image of the test circuit below, all I had to do to change between the circuits was to flip the LED connector over and attach it to the other output pins. The actual position of the LED in the lightbox is exactly the same in both cases, there is absolutely no difference in the two setups except how the LED is connected to the board.

So, Circuit 1 ran at an average input power of 90 mW and produced 63.9 lux at the sensor, for an efficiency of 710 lux per Watt.
Circuit 2 ran at an average input power of 40 mW and produced 30.0 lux at the sensor, for an efficiency of 750 lux per Watt.
By eye, there was little difference in the brightness of the LED, even though in real terms #2 was half as bright as #1. Both circuits ran at a little over 12 kHz, but with very different waveforms (Collector wrt Emitter). I'll show the waveforms later on, perhaps also with a video of the testing.

So the efficiency winner in these preliminary tests is Circuit 2, by a thin margin. Brightness winner is #1 but will definitely drain the battery much faster.

Great test TK,and of course the results are as expected.
As  i pointed out to MH,the second circuit eliminates the losses associated with charging the battery also,when a battery is used in place of your PSU. The battery will produce more waste heat,when being discharged and charged continuously,and also there are the internal resistive losses that grow as the battery voltage drops.


Brad

tinman

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #325 on: July 10, 2016, 02:52:47 AM »
You bring up lots of valid points wrt "efficiency" of a JT type flashing/pulsing light. There are many many variables to be considered, both in the circuit itself (like number of turns, core material, impedance of power source, etc) and in the behaviour of the LED, the lightmeter, etc. As far as I can tell this lightmeter is doing a pretty good integrating of the 9-13 kHz flashing of the LED so I mostly believe in its readings. I don't have "threshold" operation levels yet, that is I don't know the low voltage limit of the two circuits. It seems to be the case that the supply impedance affects the efficiency (my definition, Lux/watt input power) but I'll have to do more testing to see how much. (Power supply vs battery have different impedances.) Then there is the matter of the turns ratio of the inductor. Then again, the different waveforms that the oscilloscope sees on the input current measured across the 0.1 ohm CSR in the two cases may be affecting the calculations of the average input power, although I've made the computation using DMM measurements and they agree with the scope measures to within 10 percent or so.

So nobody should take my measurements as "solving" the issue or supporting either side of the argument _at this point_. At best, I am trying to establish a reasonable testing protocol that can be used to track down the effects of the various variables in the experiment.

@ TK

Please know that these two circuits are not the set parameters to this !friendly! competition.
As far as im concerned,both of those circuits are quite poor efficiency wise.

Also,could you post a schematic of your power measurement points,as circuit 1 is much harder to calculate,as the battery is also in series with the inductor and LED,and so some of that light output also includes energy from the battery,and so that must also be taken into account when calculating P/in. Circuit 2 is much easier to calculate total P/in,as it excludes the battery during the off part of the cycle(transistor open). So when you are calculating P/in,in circuit 1,you must also include the energy that the battery supplies to the LED during the off time of the transistor,as it is in series with the other current source--that being the inductor,and so the LED is driven by both the stored energy in the inductor,plus some from the battery as well.

This gets even harder to calculate,as during the off time of the transistor,the battery is also trying to recover a little as well,which can also created the elusion that the battery is actually being charged during the off time of the transistor.


Brad

Thanks

MileHigh

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #326 on: July 10, 2016, 03:24:08 AM »
Great test TK,and of course the results are as expected.
As  i pointed out to MH,the second circuit eliminates the losses associated with charging the battery also,when a battery is used in place of your PSU. The battery will produce more waste heat,when being discharged and charged continuously,and also there are the internal resistive losses that grow as the battery voltage drops.

Brad

Nope, what you say above doesn't make any sense at all.  First of all, you had a serious serious case of scrambled brains when you wrote that.  It's a double whammy.  I will unscramble it first, and then explain to you how it is still "scrambled" and doesn't make any sense at all.

For starters, I am going to put on my secret decoder ring:

<<<
As I pointed out to MH, the second circuit eliminates the internal resistive losses associated with discharging the battery during the transistor OFF cycle when the LED is being lit.  In the first circuit the battery will produce more internal resistive losses when being discharged continuously.  For both circuits the internal resistive losses increase as the battery voltage drops.
>>>

Brad, your text is so messed up that I am not even sure if I decoded it properly.

Moving on, you are not seeing the forest for the trees.  It doesn't really make a difference with respect to the internal losses in the battery for either circuit, your logic is flawed.  In BOTH cases, when power is being drawn from the battery, there are internal losses in the battery.  The fact that the current draw for the second circuit toggles ON and OFF makes no difference, there are STILL internal losses in the battery when the transistor is ON.

Look at TK's numbers.  The first circuit draws roughly twice the amount of current and produces roughly twice the amount of light.  If you could change the timing in the first circuit and slow it down so it draws the same amount of current as the second circuit, then chances are the LED would be about the same brightness.

So, supposing that you do that, then what do you have in terms of internals losses in the battery for each case?  Well, the current draw is the same so presumably the internal losses in the battery are approximately the same.

I am not going to speculate on further subtleties, that would have to be investigated for real on the bench.  The point that I am making is that your logic is flawed and doesn't make sense.  You have to think these things through and not just jump on what you first think is true.

MileHigh

tinman

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #327 on: July 10, 2016, 03:44:40 AM »
 author=MileHigh link=topic=16225.msg488141#msg488141 date=1468100075]



Quote
Well, I can easily see Brad having a braingasm from TK's posting so I will get a few words in edgewise.

Oh MH--please.
No need to be so childish. I know circuit 2 is more efficient through bench tests,and also for reasons i have already given to you regarding I/R battery losses.

Quote
One of the classic weaknesses on the forums is to use the term "efficiency" without even defining what it means.  Brad is someone that does this all the time.

When it comes to the JT,then it would be maximum light out as determined by visual reference-per watt in. It would also be the ability to produce actual maximum light out per watt in,and last but not least,be able to drain as much as the remaining battery energy as possible.

Quote
My line of thinking was as follows:  In circuit #1 when the LED is lit it is based on a discharge of the LED in series with the battery.  So the EMF from the battery is a "helper" to keep the LED lit.


That is correct,and i suspect that TK did not take this into account when making his calculations on P/in in circuit 1,as the battery is also delivering energy to the LED during the off time of the transistor,as it is in series with the inductor and LED. When this is added to the P/in calculations,you will see circuit 1's efficiency drops right off.

Quote
So, it suggests to me that circuit #1 may be able to extract more energy from a nearly dead battery because it looks like it will run at lower battery voltages than circuit #2.  That will likely translate into a longer run time from the same battery.

That would be easy to test.

Quote
How did I define "efficiency" for the "most efficient Joule Thief?"

The answer was the most efficient Joule Thief by my definition would be the one that has the longest run time and extracts the most possible energy from the nearly-dead battery.

I stated this to Brad multiple times but it never sank in.

LOL--now there is a big load of crap MH.
Was it not me that suggested using the J/FET ::),in order to make a JT that would extract most of the remaining energy from a battery,only to have you say that that made no sense at all.
Was it not me that posted videos showing how low i could get the voltage,and yet still have the JT circuit running-->remember your death spike saga ?. Would not a JT circuit capable of running on the lowest voltage,not extract the most remaining energy from a battery?.

In fact,your statement above is absolute rubbish,and those that were a part of that JT thread will know your talking crap. When most of us tried to explain to you the relevance of having a variable resistor on the base,so as it could be adjusted as the battery voltage dropped,you just got your back up,and said that the JT circuit has a fixed 1k ohm resistor to the base,as it is designed to run on 1.5 volts.

So stop your crap talk and lies MH,as people can see that what you are saying is absolute rubbish.

Quote post 254: 
And the pen is mightier than the bench - it is.  Suck on that and stop sounding like a miserable sourpus.

Quote post 286:
Quote
The pen is mightier than the bench Brad and my words have real meaning.


Quote post 304:
That all sounds fine and dandy except for the fact that if I wanted to do it I would need to work on a bench to iterate on a design.  Since I have no bench and no desire to do it, it's not going to happen.  I can't just put something on paper without testing it and iterating on it myself.

Quote
Now we can go back into the holding pattern waiting for Brad's expected tsunami braingasm.

Well some one had one MH,and im pretty sure it was not me :D

Seems your pen is no longer so mighty MH.


Brad

tinman

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #328 on: July 10, 2016, 03:53:09 AM »
Nope, what you say above doesn't make any sense at all.  First of all, you had a serious serious case of scrambled brains when you wrote that.  It's a double whammy.  I will unscramble it first, and then explain to you how it is still "scrambled" and doesn't make any sense at all.

For starters, I am going to put on my secret decoder ring:

<<<
As I pointed out to MH, the second circuit eliminates the losses associated with discharging the battery during the transistor OFF cycle when the LED is being lit.  In the first circuit the battery will produce more waste heat when being discharged continuously. For both circuits there are the internal resistive losses that grow as the battery voltage drops.
>>>

Brad, your text is so messed up that I am not even sure if I decoded it properly.

Moving on, you are not seeing the forest for the trees.  It doesn't really make a difference with respect to the internal losses in the battery for either circuit, your logic is flawed.  In BOTH cases, when power is being drawn from the battery, there are internal losses in the battery.  The fact that the current draw for the second circuit toggles ON and OFF makes no difference, there are STILL internal losses in the battery when the transistor is ON.

Look at TK's numbers.  The first circuit draws roughly twice the amount of current and produces roughly twice the amount of light.  If you could change the timing in the first circuit and slow it down so it draws the same amount of current as the second circuit, then chances are the LED would be about the same brightness.

So, supposing that you do that, then what do you have in terms of internals losses in the battery for each case?  Well, the current draw is the same so presumably the internal losses in the battery are approximately the same.

I am not going to speculate on further subtleties, that would have to be investigates for real on the bench.  The point that I am making is that your logic is flawed and doesn't make sense.  You have to think these things through and not just jump on what you first think is true.

MileHigh

MH

You really are lost,and it is becoming more apparent each day as to how little you understand the simple JT circuit.
The battery is also a resistor,and as the voltage drops,the internal resistance grows,and so do the I/R losses associated with that battery.

In the second circuit,these losses are only had when the transistor is on.
In the first circuit(your circuit) these battery I/R losses are not only included when the transistor is on,but they are also included when the transistor is off.

During the off time of the transistor in circuit 2,the current loop excludes the battery,and thus the losses associated with the batteries internal resistance.
In the first circuit(your circuit) the battery becomes part of the current loop during the off time of the transistor,and so also includes the I/R losses associated with the battery.

Why you find this so hard to understand-i guess we will never know.\


Brad

MileHigh

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Re: A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?
« Reply #329 on: July 10, 2016, 04:08:26 AM »
Brad:

Like I just did an unscramble and decode of what you said in posting #324, your logic is flawed and makes no sense.

I seriously doubt that TK made a mistake in his power measurements.  It doesn't make any sense.  All that he had to do was scope the voltage and current from the power supply for both circuits.

Quote
Was it not me that suggested using the J/FET (http://overunity.com/Smileys/default/rolleyes.gif),in order to make a JT that would extract most of the remaining energy from a battery,only to have you say that that made no sense at all.

Like I said, I think the chances are nearly zero that that will ever happen.

Quote
In fact,your statement above is absolute rubbish,and those that were a part of that JT thread will know your talking crap. When most of us tried to explain to you the relevance of having a variable resistor on the base,so as it could be adjusted as the battery voltage dropped,you just got your back up,and said that the JT circuit has a fixed 1k ohm resistor to the base,as it is designed to run on 1.5 volts.

I was not talking crap at all.  I tried desperately to explain to you what the true reason for having a base resistor was but you would have nothing to do with that, it was pure willful ignorance on your part.

Quote
So stop your crap talk and lies MH,as people can see that what you are saying is absolute rubbish.

You are just talking stupid gratuitous foolish idiocy, you need to blow off some steam and thar she blows!

Quote
Seems your pen is no longer so mighty MH.

My pen is absolutely fine.  You need to work on thinking straight and being able to string five sentences together that make sense.  Those are some of your biggest problems.

MileHigh