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Resistor change...Daedals 317 circuit..

LarryQ

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Yes..In series..right after the 317 but before the LD/N14001diode/Capacitor assy.

I don't have a measurement on the Batts when the circuit is ON...That may be a tough one it get..
I assume I need to take it at the Vin leg of the LM317.

I also need to get a voltage drop reading through the diode assy..I didn't take one yet.

Thanks for the help!!!


Larry
 



Gazoo

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You really need to know what the voltage of the batteries is with the LD on, and yes you would need to measure between ground and the voltage in leg of the LM317. I have a feeling it is sagging and this is what is causing the discrepancy between the calculation and your actual readings.
 

Benm

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You could also just have a not-too-good LM317 really.

Remember that you are operating the LM317 out of specification even at 6 volts supply voltage. It requires 3 volts drop from in to out to regulate, PLUS 1.25 for the reference in constant-current mode.

I know most LM317's will regulate with less than 3 volts drop, but it is not guaranteed that they will at all.
 

LarryQ

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Ok...
Voltage of the batts while the Laser is ON is 5.05 volts

Voltage drop across the Laser Diode is 2.86 volts

with the 3.9 Ohm resistor across the ADJ leg..I am getting 218 ma (measured at the sense resistor)

Cover me...I'm going for 2 Ohms

LarryQ
 

LarryQ

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Well..that was suprising....

2 Ohm only gave me 250ma at the sence resistor...

I guess this combo is tapped out.

I Finished it and closed it up....

I'm going to leave it as is....

Not a bad burner....!!!! Wish I had a power meter to be able to verify output!

Now...That makes 3 red burners...

That ought to hold me for a while.....

Oh...who am I kidding?!?!? ;D



LarryQ
 

chimo

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Larry, guess what will happen at a later date if you forget and put a higher voltage source (or perhaps fresh batteries) on your circuit. (Hint: you will not like the results).

LarryQ said:
Well..that was suprising....

2 Ohm only gave me 250ma at the sence resistor...

I guess this combo is tapped out.

I Finished it and closed it up....

I'm going to leave it as is....

Not a bad burner....!!!! Wish I had a power meter to be able to verify output!

Now...That makes 3 red burners...

That ought to hold me for a while.....

Oh...who am I kidding?!?!? ;D



LarryQ
 

LarryQ

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Batts are already brand new....

(2) CR123 Lithiums...

Besides...If I smoke this diode...I replace it with an Open can diode... ;D
 

Gazoo

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5.05 volts? Well that explains everything. If you do decide to switch to an open can you might want to consider RCR123's.
 

LarryQ

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EWWWWW....

Rechargeables??????

I hate rechargeable batteries..!!!
I like use/pitch/replace simplicity.

I've avoided using rechargables like the plague!

What is the voltage on those 3.2 each versus the 3.0 of the lithium cr-123?

Larry
 

Gazoo

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Li-ions measure 4.2 volts when fully charged. Then they drop off rapidly to 3.6 volts and go down slowly from there.. :D
 

LarryQ

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At startup, and 4.2V EACH...What's to prevent it from turning into the much heralded "Black Laser" ???

Ughhhhhh...rechargeables...

Ok......

So should I get the ones with the built in protection circuitry??

I may stop off at the battery store after work tonight...

Thanks

Larry
 

Gazoo

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I am not sure if you are supposed to get the protection circuitry if using more than one cell. Please ask at the store if you go there and let us know, or if anyone else knows please chime in here. As I recall there was some confusion about it and I don't recall what the outcome was. :p
 

LarryQ

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GAZOO!!!!

You Freaking GENIUS!!!!

I need to buy you a beer!!!

I stopped at the battery store and picked up a pair of RCR-123's and a charger!

Charged them and got 3.5V per cell!

Deciding to be careful...I replaced the (2) 3.9 Ohm Paralell resistors with a single 3.9 Ohm 1/2 watt Resistor.

BINGO!!!!!!

Current measured at the sence resistor 325ma on the NOSE!!!

Voltage at the Batteries with the laser on 6.45 Volts!!!!

Right where I wanted to be!!!!!

DAMN I wish I had a power meter!!!!

I can only GUESS at the power rating!!!!!
It's a GB diode.....

Ballpark Power guess????

THanks again Gazoo!!!

Larry
 

Gazoo

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Well Hemlock Mike did a graph..you are over 200mw's! BTW, did they know if two protected cells in series will work? From what I have been reading we are only supposed to use them in single battery applications..but I am still not so sure.

Anyway, glad that worked..I knew it would when you said you only had 5.05 volts going to the regulator. Don't let the batteries go below 3 volts each, but I think you already know this.. :p
 

Hemlock_Mike

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Larry --

At 325 mA with the GB diode, you are around 200 to 220 mW output depending on how good your lens gathers all the output. You are at the knee of the curve and I don't recommend going any higher unless you have good cooling or a LD death wish !!

Congrats --- Mike
 

LarryQ

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Thanks Mike...Yes I have a Machined aluminium heatsink 1.1" dia, .825 long solid alum...
The AiXiz module was smeared with Arctic silver 5 then Pressed in (Nice press fit @.006-.008 interfereance fit).

Not active cooling..but not bad for a flashlight mod!!!

Thanks!!!


ANd on the Cells....

All they had were the protected cells...so It didn't matter at the time...

I was lurking around the candlepower forums today...and it looks like both are routinely used in flashlights that require multiple cells.

It's overcharge/run low protection.

Anyway...She BURNS!!!!

LarryQ
 




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