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Resistors PIVR Calculations
At a given temperature, the potential difference or Voltage drop (V) across a resistor (R) is proportional to the current (I) flowing through it.
Take Nick Reeder's Ohm's Law Challenge
R = V / I
This triangle helps some people to remember that
To remember this triangle, try this: The Vase on the table Is Red
The ammeter measures the current flowing through the resistor.
The voltmeter measures the voltage across the resistor.
Assume that the meters are ideal and they have no effect on the circuit ...
Try a few Ohm's Law calculations ...
Resistors come with a power rating. This is the amount of heat that can be dissipated safely. If this rating is exceeded, the resistor will get too hot and could be damaged or even catch fire.
In these calculations ...
P = I V
P = V2 / R
P = I2 R
E = P t
Energy is equal to Power (in Watts) x time.
The SI unit of energy is the Joule so one Watt of power for one second would equal one Joule of energy.
When buying electricity, the Joule is an inconveniently small amount so Kilowatt Hours are used instead. This is still Power x Time but Kilowatts and Hours are used instead of Watts and Seconds.
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