Direct current (dc)

Definition

Direct current (DC) is a type of electrical current where the flow of electric charge is unidirectional. It contrasts with alternating current (AC), which periodically reverses direction.

5 Must Know Facts For Your Next Test

1. Direct current is used in many low-voltage applications such as batteries, electronics, and solar panels.
2. In a DC circuit, the voltage remains constant over time.
3. Ohm's Law ($V = IR$) applies straightforwardly to DC circuits for calculating voltage, current, and resistance.
4. DC can be converted to AC using an inverter, while AC can be converted to DC using a rectifier.
5. The first electric power transmission systems used direct current before being replaced by more efficient alternating current systems.

Review Questions

• What distinguishes direct current from alternating current in terms of electron flow?
• How does Ohm's Law apply differently in DC circuits compared to AC circuits?
• What devices are commonly powered by direct current?

Related terms

Alternating Current (AC):

A type of electric current where the direction of the flow of electrons switches back and forth at regular intervals or cycles.

Rectifier: An electrical device that converts alternating current (AC) to direct current (DC).

Inverter: A device that converts direct current (DC) into alternating current (AC).