Comments: Alternating Current (AC) vs. Direct Current (DC)
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can a direct current vary with time. For an example like an exponent signal, ramp signal.
Definitely a DC current can vary with time. I came to know about it from the article on askanydifference. you can search google images for "dc current diagonal graph" to see the graph
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?
Yes it can! One way to do that is through a device called an inverter.
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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