Electric Circuits Flashcards
Another name for voltage?
Electric potential difference
What happens when a potential difference exists between two points?
Charge will flow from one point to the other.
Electric current? Symbol? Unit?
A measure of the flow of charge in a conductor. Symbol: I Unit: A
Voltage? Symbol? Unit?
Electric potential difference. Symbol: V Unit: v
What do voltage sources do? What are three types of sources of voltage?
Voltage sources create a potential difference between two points on a conductor.
- Battery
- Wall outlet
- Generator
Electrical resistance? Symbol? Unit?
A measure of the difficulty charge has in moving across a potential difference. An opposition to the flow of current. Symbol: R Unit: Ohm
Ohm’s Law
I = V/R
Current in a conductor = voltage across the conductor/resistance of the conductor
Circuit
A closed path along which current can travel
True/False:
All conductors have some resistance.
True
Resistor
A device in a circuit that has some definit resistance. Resistors take electrical energy and turn it into some other kind of energy.
Series circuit
- The current through each part of the circuit is the same.
- Voltage lost across each part may be different.
Parallel circuit
- Current through each element may be different.
- Voltage along each parallel path is the same.
Equivalent resistance
It is possible to replace any combination of resistors in a circuit with a single resistor of the “equivalent resistance” of the resistors replaced.
Direct current
Voltage applied to a circuit that always drives charge in one direction creates a direct current. (battery)
Alternating current
Voltage applied to a circuit changes in a way that drives charge first in one direction, then in the opposite direction. (wall sockets, most generators)
Capacitor
A device which stores electric energy. It is charged by the battery
What does a capacitor use?
- Very rapid release of a lot of energy (camera flash, AED)
- Very slow release of energy
Parallel-plate capacitor
Two parallel metal plates with a gap between. There is a build up of equal and opposite charges on the two metal plates. An electric field exists between the plates. Some electric potential energy is stored between the plates.
What three things would allow more energy to be stored in a parallel-plate capacitor?
- Bigger batery voltage
- Bigger plate surface area
- Smaller distance between plates
Where is energy in a capacitor stored?
In the electric field between the conductors
As more lamps are put into a parallel circuit, the overall current in the power source….
Increases
