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Topic: Selecting BJT (Read 365 times) previous topic - next topic


Hi Friends,

I am new to adriuno as well as electronics, and building a project for my self learning, I am facing one issue using NPN transistor when using it as a switch.

For my testing I have 3v and 20mA current should be passing in the circuit via BJT with some current is given to base.

Now when I tried lighting an led without passing current to base my bjt it is still conducting and giving low light on led, the only change happen when I am passing current to base, led turns brighter. unfortunately I do hold datasheet for this bjt as I got this with starter kit.

Not sure what I am doing wrong and why it is conducting without base voltage.

In real use case I want to switch on a 12v motor with max 3Amps current when a high is given to base. please suggest me which NPN (or alternative) I should use since there are many and I do not want to amplify.

Another help I am looking to understand how much voltage and amps a bjt can control/handle before leaking or failing and not getting hot.

How much should be minimum and maximum base voltage and current.



for high current switch-transistor.. use a mosfet.  e.g. IRLU024 (17A) or IRL540N (35A)

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