This is an iOS app that I originally made to help students in my electronics classes to better understand the inner workings of various BJT circuits. I will often ask the students “What will happen to the Q-point if Rb was to increase?” or “What if I replaced the transistor with one that had a lower gain?”
Often the students would struggle to visualise what would actually happen. This app allows the user to adjust the values of the resistors, power supply and transistor gain by use of slide bars. The Q-point will then be plotted in real time as each slide bar is moved.
The app will also calculate in real time, the values of Ib, Ic, Vce, Icsat, Vceco. It will also calculate Vb and Ve for the voltage divider bias circuit.
You can download the app for free from the App Store.
Fixed Bias Circuit
Fixed Bias With Emitter Resistor Circuit
Voltage Divider Bias Circuit