Graphical Method for Determining BJT Inverter Characteristics

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Dirac8767
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Hi I'm having some problems with using the graphical method to determine the output characteristics, the question and the answer are all included in the document attached. I understand the process of putting the load line on the graph but for this application i have no idea what to do.

Many thanks!
 
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  • Collage of a BJT output characteristic graph with load line, a transfer curve of VOUT against VIN with marked VOH, VOL, VIH and VIL values, and an n-p-n BJT inverter circuit with a 1500 ohm load resistor and 45 kilohm input resistor.
    Question 6.jpg
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Here are some hints:

Since we are working in milliamps use resistors in kohms.

Vout = 4.5 - 1.5Ic

Vin = 45Ibase+0.65

So chose a series on Ibase and note where your load line intersects that value on the transistor characteristic curves graph.
Move across the graph horizontally from this intersection to read off the value of Ic corresponding to that value of Ibase

Substitute these pairs of values into the above equations to plot the Vout / Vin curve, as far as the noise limits given.

Does this help?