Transistor controlled led question

182

03:51:31

I have designed a simple transistor controlled led. I am protecting led with a resistor such that the voltage is 1.5v around led.

I also figured out that I can achieve same thing if I put a resistor (with a bigger ohm) between switch and transistor. 

Which one is a better design? Shoul I also protect transistor with resistor? 

I am a beginner, that would be great if you can comment.

published 12 years ago

suraj397

12 years ago

Itz not led its lamp...!!! Lol

kaan

12 years ago

Ok thats lesson 1 then. :) resistor protects lamp. Is it okay if I remove the resistor and put another between switch and transistor?

thebugger

12 years ago

1st unless you are working with powerful transistors or mosfets you should alwaya use a base resistor to limit the current,because it may lead to a saturation of the transistor or worse you might actually destroy it.

thebugger

12 years ago

The base trabsistor should be around a few kohms depending on the transistor's characteristics also you might also want to put a resistor on the collector and the emitter. If you wanna make a delayed shut down put a capacitor on the base.

kaan

12 years ago

Thanks thebugger I will try delayed shutdown

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