LED lamp

By rss@youtube.com (ciaheadmechanic0809) This is an Arduino microcontroller hooked up to some LEDs and a photoresistor. The programming cycles through the LEDs base don the amount of light that the resistor sees. The maximum and minimum lighting values are dynamically set by the system and should work out so that lower light slows...

By MaJellin I have several surface mount LEDs in 2-PLCC packages but I have never soldered before and I really dont know what I would solder them to if I had. Is there any way I could power these LEDs with a breadboard, a 5v source, a resistor and some jumper wires? I have tried just bending the pads out from t...

By JunaidKhan Here is an easy example. If I have 9 volts and connect 3300k R to an LED, I see that the voltage dropped. But what I don't understand is what does the resistor mean by 3300k? Does it mean that that’s how many electrons it will let through regardless of volts?

By The newguy11 To test the brightness I wired them up in parallel without resistors. It worked fine and the light output was very good. An online calculator said I should use a resistor (39 ohms) in front of every LED. I would also like the grid to have a high low setting, possibly mid level setting. My current pl...

By superflux I'm creating a simple Tri-State situation like "ronsimpson" suggested using a resistor ladder to give an LED multiple brightness characteristics. Sorry for the confusing title. I'm creating a simple Tri-State situation like "ronsimpson" suggested using a resistor ladder to give an L...

By DrOC I can easily convert the resistance output of the sender to voltage using a voltage divider. However the "other" dividing resistor has to be between the sender and the voltage supply i.e. I can not connect the "other" resistor between the sender ground and the actual ground.

By Sparrow338 I've tried adjusting the values of the components and the best I can get the circuit to do is to make the LED fade on, put after that it just gets stuck on and doesn't fade back off. To do this I changed out the resistor that goes from pin 7 to ground from a 4.7k Ohm to a 1k Ohm.

By bountyhunter Resistor RD affects the dot sweep rate: less resistance makes it sweep faster. This can be user adjusted based on preference. The LM3914 dot select pin is left open to select single LED (dot) mode, but in reality, about four or five LEDs are lit at any one time as the thing sweeps the display wit...

By Collin Cunningham In this installment of the MAKE presents series I explain - how to build a leyden jar, how the capacitor was invented, and how to use one to light an LED. I incorporated some viewer requests from MAKE presents: The Resistor and I'll be adding more in the next installment. Please a comment if the...

By R2-D2 Can I use just one resistor for each group of LEDs (R7, R8 and R9) instead of one for each of the six branches in the LED groups? If I need a resistor for each branch (of three LEDs), I have calculated them to be at 75Ω each. R = (1.8 volts dropped / 0.024 Amps) = 75Ω

By Chris Connors Many instructional materials for learning to work with electricity and circuits are based on 9 volt batteries. Often they start by having the experimenter place a resistor in series with the LED to reduce current flow, save on battery life and keep the LED from getting fried. Having to use a...