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 Versus Alternating Current. Batteries, fuel cells and solar cells all produce something called direct current (DC). The positive and negative terminals of a battery are always, respectively, positive and negative. Current always flows in the same direction between those two terminals.