The Index consists of liquid United States dollar-denominated, high yield corporate bonds for sale in the United States, as determined by International Index Company Limited. HTG is based in Boston, MA.
In direct current (DC), the electric charge (current) only flows in one direction. Electric charge in alternating current (AC), on the other hand, changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction. Most of the digital electronics that you build will use DC.
Direct current and alternating current have different advantages and disadvantages that make them useful for different applications. Most consumer electronic devices, like cellphones, flat screen TVs and even electronic cars, operate with direct current.