These are the syllabus dot points:
# gather, process and present secondary information to discuss how shortcomings in available communication technology lead to an increased knowledge of the properties of materials with particular reference to the invention of the transistor.
It doesn't specifically state "explain how a transistor works". My interpretation of this dot point is to mention where transistors are used and how they are better than those valve thingos (i forgot what they're called).
# identify data sources, gather, process, analyse information and use available evidence to assess the impact of the invention of transistors on society with particular reference to their use in microchips and microprocessors.
For this, you have to mention the good and bad impacts (bad might be problems with it) on society. I think you need to know what a microchip/microprocessor so you can justify your assessment of the transistor. Still, I don't think you have to know the transistor in great depth.