Comments: Alternating Current (AC) vs. Direct Current (DC)


Comments 7 comments

  • can a direct current vary with time. For an example like an exponent signal, ramp signal.

    • In theory, DC is not supposed to vary with time, but it practice, you will often find direct currents that vary. For example, a rectified AC signal or the output of a buck or boost converter will have some ripple to it (even though it’s usually considered “DC”). Even a battery will lose some of it’s voltage over time.

      This post gives some good examples with graphs.

  • Can direct current be converted to AC current?

  • Higher voltage means low current? What if low voltages, will it means low current too?

    • That’s not necessarily true. If we are talking about converting AC or DC to a different voltage, then the maximum possible current will change. If we convert voltages (in either AC or DC), then power stays the same (assuming 100% efficiency in your converter). Since P = V * I, if you decrease voltage, then current must rise to keep power the same. Hope that makes sense.

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