“WHY IS IT CALLED VCC? The positive voltage symbol is called VCC because of old naming conventions. VCC was the voltage supplied to the collector side of a transistor in common transistor circuits, usually through a resistor or some other components. The collector is where the “CC” comes from. You’ve used a bipolar junction transistor throughout this book, but there’s another type of transistor called a field-effect transistor (FET). The pin that equals the collector on this type of transistor is called the drain, so the voltage that was supplied to the drain side of the FET was called VDD.”