Plusivo DMM - 6.2 Joules Law for Electrical Power

6.2 Joule's Law for Electrical Power
Electric power is the rate of the emitting power from a resistor per unit time, the unit
of power is watt.
𝑃 = 𝐼 · 𝑉
𝑃 = 𝐼
2
· 𝑅
𝑃 =
𝑉
2
𝑅
P is the power on the resistor.
I is the current through the resistor.
V is the voltage around the resistor.
R is the resistance.
Note: There are many types of emitting power, it may be a rotary power, light, heat, etc.
6.2.1 Example
Calculate the power on the resistor.
To calculate the power on the resistor, we need any two values of these: Voltage,
Current or Resistance.
In our example, we have the voltage and the resistance, so we can use this formula:
𝑃 =
𝑉
2
𝑅
(3 𝑉)
2
510 Ω
= 0. 0176 𝑊 = 17. 6 𝑚𝑊
24
Mastering the Art of Measurement (Digital Multimeter) r.01 www.plusivo.com