Driver help

hi, i'm new in this, so i need your help, the problem is this:

i watched a video on youtube, a phazons video i think.
I bought everything but not how i saw it:

1.- A Lm317T The video says Lm317
2.-A 500 ohms pot the video says a 25 ohm pot
3.- 2 res 10ohms the video says 2 res 10 ohms lol XD
4.- 1N4007 diode the video says 1N4001 diode
5.- 47mf 25 V capacitor The video says 47mf 35 V capacitor.

well. when i connected everything i used 2 batt. 1.5V each and i used a led of 3V, when i turn the pot the led lights perfectly. i did the same with a 6V led and 6 V of power.

Then, i soldered evrything, but when i powered it up...Nothing happened.
I changed the resistors, the LM317, the diode, the capacitor... and nothing happened.
I connect the multimeter in the end of the circuit ( Where the laser is sopossed to be) with the 6V batteries and when i connect the led,, the power lever decrease to 1.2 or 1.4.
I connected a power sorce of 6V and it still not work.

Does anybody knows why is this happening?


p.d srry about the gramatic, i'm new in this... and in the english too!! lol

You should probably read some texts on basic electronics. Google has links to many if you search for that term. Otherwise, you might want to check out some of the tutorials, especially the DDL (Daedel) circuit, which is pretty much what you constructed above. With exception to the pots, the components that differed in your part list and the video are just variants of the same part, so you don't need to worry about that. The real problem is that you need to be more familiar with circuits in general before you continue, or you'll just end up burning stuff out.

thanks for the help.
now, i have one more question:

if i bridge the middle pin with the right pin ,the left pin will be the V out, is this right?
or, if i connect the middle pin with the left side, and this side connectedto the V out of the LM317, is this right too?
here is the pic

I have built that circuit with that pot...and in mine i put a connection between the middle and the left one...when the adjuster thing is pointing up...Good luck

It doesn't matter which end you join to the middle, when you connect the outer pins to the circuit turning the shaft clockwise will either turn the output up or down.
I have attached a drawing of two pots (different kind but work the same) showing the wiper in the same position, the one with wiper joined to left hand pin gives 0 ohms out, the one with the right pin joined to the middle gives 100 ohms out, hope that helps.


The reason you join the middle pin (wiper) to an end pin is to ensure that if the pot fails the circuit will see full resistance rather than open circuit.

Regards rog8811

Ok Thank you, now, does anyone knows why the pwer level decrease to 0.0 V when i connect the led for the test, or how can i know if a part is burned?

And again thaks for your help.

Ok, i solved everything above, now i'm using a 3V led, it lights perfectly when i turn the pot, but in my multimeter i only have a 110mA output. my queston is: what can i do to raise the output power?