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Bipolar Junction Transistor DC Biasing Calculations Example.

The model of the circuit we are biasing.

It is Number Crunching Time! Tonight we set the DC Bias of the circuit shown in the first diagram. Once we do that we will run several Qucs simulations of the circuit with the numbers we calculate. We will do those simulations with different values for

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Negative Feedback to compensate for Beta Variation in BJTs.

Negative FB Biasing.

In the last post, “Using the Transistor Model – Our first circuit“, the wide tolerance of β (hFE) in the transistor specifications is making life complicated. “Complicate our life will ya!” We will fix the problem by complicating the circuit to reduce the complications. Seriously, we will add several more resistors

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Using the Transistor D.C. Model – Our first circuit.

The first circuit we will analyse.

In the post “The Basic DC Model for a NPN Bipolar Junction Transistor” we came up with a generic model for a transistor and in the last post “Reading a Datasheet for our DC Transistor Model Parameters” we assigned values to the parts of the model based on

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Reading a Datasheet for our DC Transistor model parameters.

The model for the active region

We have created the form of our DC model for our transistor in the last post, “The Basic DC Model for a NPN Transistor“. However, there are lots of unknown values that we need to determine to build a model for the actual transistor we are going to

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The Basic DC model for an NPN Bipolar Junction Transistor

Modified Current Definitions for our NPN Transistor Model Discussion

There are two ways to create a model. One method is to know how the pieces are parts inside the device operate and use these principles to add all the pieces and parts and their interactions together to develop a “white box” model. The opposite

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Circuit simulation software – Qucs

A Simple model in Qucs

I spent a fairly large about of time trying to find some simulation software to meet the needs of this blog and the readers of this blog. Some of the criteria I used in the search were:

Free or very low cost: Most of us do not have hundreds

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Design, Models, and Simulations

Design, if you are lucky, is based upon some calculations developed from a model of the thing you are attempting to design and construct. Often, as we have seen with the sheet metal brake project you are not lucky and we are left “flying by the seat of our pants.” Other times we know the

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A Homemade Box and Pan Brake – A better way

Sometimes… sometimes… you just gotta admit it. There is a better way and it ain’t yours. Actually that is what makes the net a great thing. There is always something to learn if you remain open to learn it and isn’t that the true goal: To become better and better. The only thing I wish

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Stiffening up the Homemade Box and Pan Brake

The brace to stiffen the box and pan brake.

After doing a lot of work in previous tests I determined the brake could get the job done on small pieces of metal but just could not get it done on longer pieces because the hinged board was bowing when I applied the force necessary

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Theory Vs. Reality: First Comes the Assumpton Then It All Goes to Hell

This is a post where I could think of a lot of very funny names and titles, but when it came down to the actually writing one I chose the term I most often use in professional life. “First comes the Assumption Then It all Goes to Hell”. Very often the calculations and number crunching

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