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Modifying the DDL circuit

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SargeMX5

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Oh ok. Thats interesting to know. What about them batteries everyone buys from DX? The CR123A rechargeables i think which are 3.0 or 3.6v. Would they be good enough?

And also i just got a new open can diode from a DVR11D, whats a safe amount of current i can be putting into this diode without killing it? I want it so that it can burn stuff and the beam is slightly visibly at night. Im not risking the pot anymore, so what i will do is a dummy test load to match the mA i am after then measure the resistance of the pot where the reading is say 200mA and get a resistor and solder it were the pot should sit.
 





Gazoo

Gazoo

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For batteries I would recommend these:

http://www.dealextreme.com/details.dx/sku.3273

For the charger:

http://www.dealextreme.com/details.dx/sku.936

If you are going to order from DX and you want a decent host:

http://www.dealextreme.com/details.dx/sku.4171

You can use the resistor that comes with that flashlight with the LM317.

The safe current for an open can is still a bit debatable, but ~400ma's should give you a long lasting experience. The 3 ohm resistor that comes on the flashlight driver will give you 417ma's when soldered to the LM317.

You don't need pots unless you eventually want to build a labby with a TEC. But you will need goggles. I recommend the wicked laser lasershades.
 
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SargeMX5

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Will 350mA's be under powering the diode? 417 sounds scaringly high(from my experience) I'm going to buy all that gear as soon as i get money in my paypal.
 
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SargeMX5

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OK guys. Instead of starting a new topic i thought id bump this up and post my final results.

Using the DDL driver and a dead diode as the load with a 1ohm resistor running between the +ve output and +ve of the laser, at full pot turn(lowest resistance on the pot) i am reading 208mA at 2.7 volts.

Running of 4xAAA(new duracells).

Does this sound right. I believe it does. Is 208mA a good current to feed to a diode and still have a good lifespan?
 
phenol

phenol

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with 2x10 ohms in parallel, provided Rpot min is about 0 ohms, the current should be 250mA. since you have a DMM, you could measure the input voltage with the circuit powered and see how far down it drops. you could also measure the voltage across both resistors + pot (between Out and Adj pins of LM317) and verify if it is about 1.25V. If lower, the regulator is dropping out.
 
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chido

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SargeMX5 said:
OK guys. Instead of starting a new topic i thought id bump this up and post my final results.

Using the DDL driver and a dead diode as the load with a 1ohm resistor running between the +ve output and +ve of the laser, at full pot turn(lowest resistance on the pot) i am reading 208mA at 2.7 volts.

Running of 4xAAA(new duracells).

Does this sound right. I believe it does. Is 208mA a good current to feed to a diode and still have a good lifespan?
Click to expand...
How do you have your multimeter set? you're supposed to set it at mV, (milivolts) when you measure like you did with the resistor, you look for voltage, and that voltage will be the same as your current. Also don't use 4 AAAs, if you can use 6 nimh rechargeable batteries, that'd be great. You need at least 6v for the driver to work, but if you put in 6v exactly, as soon as the batteries are drained out your regulator will start dropping out. (specially with alkalines since they sag a lot) But if you don't have any nimh you can still use the alkalines, but use 5 or 6 since they don't keep the same voltage with a load. ;)
 
S

SargeMX5

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The multimeter was set to 2000m for when i went to test the current, because it went out of range when i had it on 200m. then i put it on 20 to measure the actual voltage. do those readings look right
 
Gazoo

Gazoo

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SargeMX5 said:
OK guys. Instead of starting a new topic i thought id bump this up and post my final results.

Using the DDL driver and a dead diode as the load with a 1ohm resistor running between the +ve output and +ve of the laser, at full pot turn(lowest resistance on the pot) i am reading 208mA at 2.7 volts.

Running of 4xAAA(new duracells).

Does this sound right. I believe it does. Is 208mA a good current to feed to a diode and still have a good lifespan?
Click to expand...

DO NOT use only 4 batteries. I bet your regulator is already dropping out. I am running a SenKat diode at 250ma's and get 3 volts across the diode. Do as phenol suggested, measure the voltage between the adjust and output of the regulator...it should be 1.25 volts.
 
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