What Is a Field Effect Transistor?
This article will discuss one of the two main types of semiconductor transistor, the field effect Transistor or FET. The other type is the bipolar junction transistor or BJT. Active devices, vacuum tubes and transistors will change how they pass current depending on how the active device is biased. For simple diodes, made up of an anode and a cathode, (same for both vacuum tube and semiconductor diodes), a forward biased device has a negative voltage applied to the cathode and a positive on the anode and will pass current with only a small voltage drop across itself. A reverse biased diode has negative voltage on the anode, positive voltage on the cathode and will block current flow as if it were a bias-controlled switch. The more complex active devices, vacuum tube triodes (anode, cathode, grid) pentodes (anode, cathode and three grid layers) and so on, and semiconductor transistors will act generally like diodes when reversed biased. When forward biased, they will conduct current, bu
