# Calculating Quiescent base current

I am given a question relating to a bipolar junction transistor. The information I am given in the question is shown below.

I am first asked to select a quiescent point from the graph to find $V_{ceq}$ and $I_{cq}$ which I did by choosing the midpoint of the load line giving $V_{ceq}=10V$ and $I_{cq}=12mA$. I am then asked to find $I_{bq}$ using the information I have just calculated and the information from the question.

I am assuming I use the equation $I_{bq}=\cfrac{I_{cq}}{\beta}$ but I am unsure of how I work out what $\beta$ is without being told it in the question. Or is there another equation I can use to calculate $I_{bq}$?

• Your expression for Beta involves 3 terms: Beta, base current and collector current. Do you see any two of them anywhere? – WhatRoughBeast Jun 1 '14 at 21:33
• The graph has plots for collector current at different values, therefore would I work out the value of one that passes through the quiescent point? – Gurn64 Jun 1 '14 at 21:37