Current and Resistance Flashcards
Electrical Currents
- Moving electrical charged that form a electrical current
- Chemical energy from a source (cell or battery) causes charged to move through a conductor (wires), carrying energy to an electrical device or load (cellphone, light bulb, etc. )
What is the symbol for current and what is it measure in:
The symbol for an electric current is “I” and it is measure in Amperes “A”
A load resists the flow of current
- A load is a device that converts electrical energy into another form of energy.
- As electrons pass through the load, they loose energy as the electrical energy is converted to another type of energy.
- The electrons in the current collide with atoms that make up the load or with each other and the collisions interfere the flow of the current.
What is the symbol for resistance and what is it measure in:
The symbol for Resistance is “R” and it is measured in ohms “Ω”
How does resistance have to do with how a light bulb generates light?
This is because when the charged move from a large wire (electrical cord) into a very thin wire (filament). Due to the fact that the charges have less room to move in the filament (because the filament resists the movement of the charges), they collide with atoms so hard that the filament gets very hot making it light up.
How do you measure the current?
- In order to measure the electric current you have to use an ammeter. The ammeter is an instrument used for measure electric current in amperes.
- in order to measure the current you have to make sure that the ammeter is connected in a series circuit with the target component.
How do you measure the voltage?
- in order to measure the voltage you have to use something calle a voltmeter which is an instrument used for measuring electric potential difference (voltage) in volts.
- to use it voltmeters are connected in parallel with the target component.
How to find the missing component:
V = I x R
I = V/R
R = V/I
