916 B
916 B
#notes #school #electricity
Summary:
- Voltage is the difference in charge between two points.
- Current is the rate at which charge is flowing.
- Resistance is a material’s tendency to resist the flow of charge (current).
- Water = Charge(Coloumbs)
- Pressure = Voltage(Volts)
- Flow = Current(Amps)
- Hose Width = Resistance(Ohms
Equations
- V = Voltage in volts
- I = Current in amps
- R = Resistance in ohms
Solving for Voltage:
V = I * R
Solving for Current:
I = V / R
Solving for Resistance:
R = V/I
Applying Concepts
If a resistor has a 20 mAh current rating, and it's being powered with a 9 volt battery.
To find the appropriate resistor for the LED, you solve for resistance with R = V/I, where V=9 and R = a number less than 0.02, like 9/0.018 = 500, so you would want a resistor with a voltage at or greator than about 500 Ohms.