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some basic questions on drivers


New member
Dec 19, 2019
Hello guys,
im just looking through different driver options and there are some upcoming questions...for the case that the answers to my questions are to be found somewhere in this forum, i beg your pardon...scanning a forum for the answers might be possible, but timeconsuming sometimes, also its not my native language and i dont comprehend the context as fast as it may seem, when you read my post.

So to the driver, i actually only know where to hook on the laser and the power.

The power, from PSU or my batteries, will be hooked to 12V, right? So what is the 5V TTL and the FAN for? I suppose its not the same fan like on a motherboard, its not really meant to be used for cooling, is it? I feel like i already asked somebody about that, but if i did i must have forgotten.

Other question is about the powerspektrum of the driver, the usually go, for exampla, from 200ma-2A. Now what if i attach a smaller diode that cant handle 2A...it looks like some drivers dont have these potentiometer wheels, or am i just overlooking them and there has to be one? And if there is one, i guess im supposed to turn it to - , as far as it goes, power on the diode and then slowly turn to +, until i feel like i have the amount of output i want? I hope i dont have to get into the Multimeter-stuff, do i? Electronics really isnt my field...i prefer building stuff like airguns or mechanical shit of all sorts :)

thanks for answer in advance....


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Well-known member
Sep 12, 2007
Yes, 12V supply goes to the 12V input terminals. TTL (short for transistor-transistor logic) is for controlling the output of the driver. Commonly 0V for off and 5V for on, but typically left floating also allows ON. It depends on the driver. You can usually leave these pins unconnected. I think the fan is simply an optional connection point for you to plug in a 12V fan for cooling the laser. You may be able to trace out the board to see for sure. You can usually leave these pins unconnected.

The blue device in the center is the trimpot used for current adjustment. It is advised you set the drive current before hooking up a laser diode. Use the search term "test load" for instructions on this.

As for drivers without a trimpot, the current is fixed. Consult the specifications on the sale page for the set value.