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ArcticMyst Security by Avery

DIY Homemade laser diode driver

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Daedal

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Stump, it looks good in the pictures... let us know what you get on the test load.

What's your input voltage?
What's your output voltage?
Is your current looking good?

:)

GL;
DDL
 
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DDL I have 5 Ohms across the adj. and a 10 Ohm test load and the results are: Output 2.34v and 208 ma
 

Gazoo

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You should be getting closer to 250ma's. What is the voltage of the batteries with the load applied.
 

Gazoo

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The regulator is beginning to drop out. You really need a minimum of 6 volts for it to regulate properly...this explains why you are not seeing 250ma's.

The formulas are 1.25/ohms = current.
1.25/current = ohms.

1.25 is the reference voltage the regulator uses and you should always see that voltage between the output and adjust pins of the regulator. ;)
 
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Should i use a 9 volt then

or will the drop be less with the diode since i am using a 10 ohm load now
 
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i just tried a silicon diode instead of the resistor for the load and got 250 ma but the out voltage was over 5.
 

Gazoo

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Don't use those little square 9 volt batteries as they will not power it for long and are not made to deliver high currents.

If it was me I would get a 6 AA or AAA battery holder. You could use Alkaline or Nimh batteries and it would a no muss no fuss solution. Or you could use a pair of AA li-ion batteries.

At 5.3 volts, I the regulator will be out of regulation with the GB diode hooked up. I know this isn't what people want to hear but others have had problems even using a pair of CR123's. The voltage sags to the point the regulator begins to drop out.
 

Gazoo

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stump56 said:
i just tried a silicon diode instead of the resistor for the load and got 250 ma but the out voltage was over 5.

Because you are not putting enough of a load on it. A silicon diode has about a .7 volt voltage drop. You need 4 silicon diodes hooked in series to simulate appx. what a GB diode will pull.
 
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what type of li ion AA Will the energizer type work i thought they were 1.5 volts apiece
 
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