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Subscribe to this list via RSS Blog posts tagged in NPN BJT Transistor

Posted by on in Development, Software and Tools

This blog post is about determining the value of the base resistor of a MMBT3904L, which is ON Semiconductor's variant of the general purpose 2N3904 NPN  Bipolar Junction Transistor (BJT), when used as a switch. The value is determined when the transistor is in the common emitter configuration. Sounds like a simple task and so it should be too. However, as we have commented many a time in our blog posts tasks that appear to be easy never are.  Hence, while undertaking this task we decided to follow Lao Tzu's (Who? - Ed) advice, which he elegantly formulated in the following quote: 

Do the difficult things while they are easy and do the great things while they are small. A journey of a thousand miles must begin with a single step - Lao Tzu.

So, as he has suggested the sensible approach in determining  the value of the resistance of the base resistor of a BJT is to perform the calculation a step at a time, as we demonstrate below.

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