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transistor trouble

jasonshader

Hello element 14, I am beginning to learn how to build simple circuits with leds and tried using a transistor and having problems. My leds are lighting up without a base current at all as soon as I connect collector and emitter. Any ideas on what im doing wrong?

  • Hi Jason,

     

    there are a number of things that could cause this including not having the circuit wired as you intended.  A circuit diagram and a photo would help.  Things like whether you are trying to use the transistor as a constant current source or as a switch are important.  What is the power source, type of transistor, etc.

    Frank

  • Jason you have some to the right place for help. There are some real bright and talent people that frequent this site, who are willing to not only troubleshoot your problem but give you the knowledge to understand. One of the keys to getting that answer is providing sufficient information. As was suggested by a drawing or in technical terms a schematic of your circuit will help people zero in on the answer.

     

    You could hand draw a schematic and take a picture to post or use a number of graphics programs to generate the drawing. KCad and Fritzing are two that are for electronic design that come to mind. I work primarily with Linux. It looks like Fritzing has a MS Windows install.

     

    Before you get discouraged stop and think. The schematic software that you may have to learn, is just one more tool that will help you explore electronic. It makes it easy to document what you are doing.

  • If you connect the LED to the base instead of the collector, the LED may light up, but it probably isn't good for the transistor.

  • Like the others said  - show us a diagram or a photo !

     

    (and maybe tell us what you want to happen in the circuit)

     

    MK