A transistor is a tiny electronic switch that opens and closes really fast, and GaN has several advantages over silicon when used in transistors. Not only are GaN transistors smaller than silicon transistors, but they can carry more power, switch faster (around 40 million times a second, roughly four times faster than silicon transistors), and they are much more power efficient.While silicon transistors have a power efficiency of around 87%, GaN transistors boost this efficiency to over 95%.The reduction in transistor size means that newer GaN USB chargers can be physically smaller than the older silicon technology chargers. And while it’s nice to have smaller chargers, it is the increased efficiency that is the most important factor when it comes to USB chargers because the more efficient an electronic component is, the less waste heat it generates.Consumers are, understandably, concerned when chargers feel hot to the touch. While it is common for chargers that use silicon transistors to get to the point of almost being too hot to touch, I find it rare for a charger using GaN technology to feel mildly warm.The faster switching also means that a GaN transistor inside a charger can have better control over the charging and respond to events such as overheating or overvoltage much quicker than older transistors could, making them safer in use.