Need Help With Using Arduino Act As A Switch To Power LED(s) Using ... Home » Arduino Led Resistance Transistor Mpsd » Need Help With Using Arduino Act As A Switch To Power LED(s) Using ... Maybe your like Arduino Led Sans Resistance Arduino Led Specifications Arduino Led Strip Voltage Drop Arduino Led Voltage Drop Arduino Led Voltage Meter Need help with using Arduino act as a switch to power LED(s) using Transistor Projects General Guidance AnkurD521 March 16, 2018, 3:56am 1 I am using a BC547B NPN Transistor coupled with an Arduino UNO to act as a switch for an LED strip(consists of four small LEDs is series) powered through an external DC Battery. I am a complete beginner to electronics,so i tried to implement the circuit at Transistors - SparkFun Learn .I connected pin 8 of Arduino UNO to the base of transistor. The problem I am facing is that the LED(s) light very dimly when pin8 is set to high.When the LED(s) are connected directly to the battery,they light properly,so the battery being discharged is not an issue.There are a couple to things I noted however: 1)If I connect the base of transistor to 5V of Arduino, LED lights properly. 2)Using any other pin of arduino still results in the same problem. 3)Mysteriously, If I touch the base resistance(10k ohm) with bare hands,the LED(s) light up perfectly.This behaviour does not depend on the state of pin8. What could be the issue ? Please see attached circuit diagram(sorry for poor quality), I have also attached datasheet of transistor if it helps. Circuit Diagram.png704×367 6.74 KB 410427.pdf (181 KB) Electrical wiring lights with arduino AnkurD521 March 16, 2018, 4:56am 3 Thank You for the reply.You were right, I omitted the pinMode statement in setup loop.The LED are lighting perfectly now, and I will add a resistor as you suggested Related topics Topic Replies Views Activity Transistor Problem Frequently-Asked Questions 23 9226 May 6, 2021 LED turns on when resistor is touched General Electronics 16 1415 October 27, 2023 [Solved]Why is my transistor switch powering the LED even though Arduino is .... Motors, Mechanics, Power and CNC 7 5850 May 6, 2021 NPN switching transistor help *SOLVED* Interfacing 4 1974 May 6, 2021 LEDs und Transistoren Deutsch 27 8147 May 6, 2021 Tag » Arduino Led Resistance Transistor Mpsd Transistor For Simple LED - General Electronics - Arduino Forum Single Transistor Constant Current Power Led Driver. - Arduino Forum Transistor Controlled LED Ring And Help With Resistor Calculations Power An LED With A Transistor - General Electronics - Arduino Forum Clarification And Help With Transistors In LED Matrix - Arduino Forum Using A Resistor And Transistor - General Electronics - Arduino Forum General Base Resistor Transistor Calculation - Arduino Forum MOSFET As A Switch - Electronics Tutorials
