Drop voltage too hight

[marielalano14]

I just assembled my first circuit using just a transistor and a resistor, so I feed my driver with a single li-on cell. It does not work, i've read just now about the LM317T needs Vf+3 V.
Is there any transistor wich drop voltage is less than 1V?
my laser spec:
2,5V
0.8A

 

[RedCowboy]

What laser diode are you using ?

You could try a LT1085

You could use a couple of AMC7135's
Each AMC7135 will add 350ma so 2 will give you 0.7A but I read that someone was concerned about them being noisy.

 

[paul1598419]

There have been some failures of the LED drivers AMC7135. You could consider a SEPIC driver, but would likely have to buy it.

 

[marielalano14]

It's a sharp diode from ebay.. no problem about the noisy as long as it can work correctly. Is there some guide that shows how to connect the 2 AMC7135?

 

[paul1598419]

Some diodes are less susceptible to noise, but that doesn't include all sharp diodes. It's primarily the greens, IIRC.

 

[RedCowboy]

AMC7135 - DC LED Driver CC [3004] : Sunrom Electronics