LED Dimmer With Potentiometer

the pot is connected wrong .. it must be connectd between (+) and (-) of the power suplly or battery and connect the middle dip of the pot to the led anode or to the regolate resistor..

I agree, this circuit is far from perfect. However, dont say its "wrong". I suppose ProtoFire would like to demostrate that the number of photos is proportional to the current of a LED. Just a guess and interpretation of his description. Unfortunately with a maximum current of 4mA he is far away from what ECs LED get consume. ECs LEDs are bright at 20mA and work up to 39.9...mA by default. With a constant resistor of 200Ohm instead of 1kOhm you can go to that limit. On the other extreme 990Ohm + 200Ohm will cause a nice dark 3.5mA current. Note: Always connect all 3 terminal of a pot. There are good reasons why. In this circuit its not dramatic, but there are circuits like amplifier were an open 3rd terminal might cause even a damage to it.

Does nobody see what just happened here??..

I do my uh lord' pick me, pick me

I agree with what everyone else has said here with the Pot connected incorrectly in the circuit. Take a look at my DC potentiometer circuit to compare

No, I'm not talking about the loose end of the pot (which btw doesn't hurt a damn thing when used in similar small scale testing/experimentation applications like this!) - scroll back within 24hrs prior to when this circuit was posted, keeping an eye out for mine and protofire's previous post to this one. You'll see what I mean...

Wow, so much controversy over a potentiometer. 1. First, the pot is actually just fine connected the way that it is. The third leg would be used in something like a resistor divider where you are creating a reference potential. Here it is used as a variable resistor. By using the wiper on the pot to position the center tap on the restive element, you are in effect adding or subtracting the amount of material that the current has to pass though and thus changing the resistance. 2. The low current is actually just fine for the LED if the LED is used as an indicator and you don't wish to see spots after viewing it. Agreed most LED's will work with 20 mA, but they are often easily seen at these currents as well. It also maters which led you use as the forward voltage drop of that LED is important for calculating actual current. I have adjusted the LED properties to match the OVLGB0C6B9 and make it apear brighter.Take a look at the data sheet's current vs intensity cahrt here: http://www.digikey.com/product-search/en?mpart=OVLGB0C6B9&vendor=365 The circuit here is actually part of a small starter kit i am using to teach some basic electronics. The values are the prototype values used and i can assure you it is quite visible. I do appreciate all the comments!