I have been trying to design and later assemble a simple class A common emitter amplifier myself and have been trying to learn on my own how to do this but am stuck and have been for a while because I don't understand how to read and interpret the datasheet(ON Characteristics) in order to find the proper values I need to design this circuit. I understand the circuit and how it works and what the different values in the circuit mean, but I would like to build a circuit from the start and calculate any values I need based on the datasheet. The problem is any example I see has values given already(such as load resistor value or collector current value) and I don't know how I would figure this out using a datasheet. I am confused by the 5 values given for the DC current gain on the datasheet and as a result cannot figure out how to find the resistor values I would need. I also understand the characteristic curve to some extent but don't know where it comes from. Is it something I draw using the DC current gain values? Is this why there are different values given? Is it something given by the manufacturer? Do I choose a resistor value to use to calculate collector current or do I use collector current from the datasheet to find my resistor value? It's like there are one too many unknowns for me to create a simple class A amplifier and I don't know where to actually start in order to start making the calculations. I know once I have one value I will easily be able to make more calculations but don't know what this value is or how to find it. For reference I am attempting to use a 5v supply and a 2n2222 transistor but I eventually want to be able to create this circuit with different sources and transistors. Thanks in advance and hopefully this isn't a dumb question.