BJT Biasings for iOS

By brad, June 29, 2013

This is an iOS app that I originally made to help students in my electronics classes to better understand the inner workings of various BJT circuits.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.

Home Screen

Here you can select one of the three biasing circuits.
HomeScreen

Fixed Bias Circuit

You are able to adjust Rb, Rc, Vcc and β. The Q-Point will be plotted in real time as the sliders are adjusted.
FixedBias

Fixed Bias With Emitter Resistor Circuit

You are able to adjust Rb, Rc, Re, Vcc and β. The Q-Point will be plotted in real time as the sliders are adjusted.
FixedBiasEmitterResistor

Voltage Divider Bias Circuit

You are able to adjust Rb1, Rb2, Re, Rc and Vcc. The Q-Point will be plotted in real time as the sliders are adjusted.
VoltageDividerBias

  • Tim

    Can you make this available in the UK app store too please

  • Ted

    What’s the app called. I tried all kinds of names on my iPhone!?

  • brad

    Hi, sorry for the late reply guys. I actually stopped paying the yearly fee to make apps for the app store and so they take the apps off of the store because of that. Sorry!