Final answer:
High-power transistors can be made in both NPN and PNP configurations, functioning as electric valves to control and amplify electrical current in circuits.
Step-by-step explanation:
High-power transistors can be manufactured in both NPN and PNP configurations. These devices are essential components in controlling electrical current in various circuits. A junction transistor, for example, is comprised of an n-type semiconductor (emitter), a thin p-type semiconductor (base), and another n-type semiconductor (collector). When voltage is applied, it allows a small base current (IB) to control a larger collector current (IC), essentially acting as an electric valve with current gain functionality. This principle is key in electronics for amplifying or switching electrical signals.