AC and DC currents
Currents produced by batteries: direct currents (DC)
- direction of the flow of positive and negative charges does not change in time
- direction of current (direction of flow for positive charges) is constant in time
- potential difference (voltage) between two points of the circuit does not change sign in time
Household electricity-->produced by generators: alternating current (AC)
- direction of the current reverses periodically in time
- voltage (tension) between two points of the circuit changes sign periodically in time
- 60 cycle alternating current: current reverses direction 120 times a second (two times during one cycle)