- #1
fisico30
- 374
- 0
Hello Forum,
electrical power is current times voltage.
Current is charge per unit time, crossing an hypothetical surface: the more people cross a door per unit time the higher the current.
Voltage is energy per unit charge: the more energy each person crossing the door, the more the power.
So to have large power, we need lots of people crossing the door, each with a high (kinetic energy), correct?
In some cases we have high voltage, low current, hence low power: that means few charges are moving across a surface but those few charges have high energy...
The max power theorem tells us that in the connection between a source and a load, the max power is transferred at a certain optimal situation, when there is a large number of changes (not the largest) with large energy (but not the largest)...correct?
All devices need power: some need high current and low voltage or vice versa...why?
thanks,
fisico30
electrical power is current times voltage.
Current is charge per unit time, crossing an hypothetical surface: the more people cross a door per unit time the higher the current.
Voltage is energy per unit charge: the more energy each person crossing the door, the more the power.
So to have large power, we need lots of people crossing the door, each with a high (kinetic energy), correct?
In some cases we have high voltage, low current, hence low power: that means few charges are moving across a surface but those few charges have high energy...
The max power theorem tells us that in the connection between a source and a load, the max power is transferred at a certain optimal situation, when there is a large number of changes (not the largest) with large energy (but not the largest)...correct?
All devices need power: some need high current and low voltage or vice versa...why?
thanks,
fisico30