Electric Power
Electric Power
Voltage and current are 2 basic parameters of an electrical circuit. But, solely voltage and current don't seem to be ample to specific the behaviour an electrical circuit part. we tend to basically have to be compelled to apprehend, what proportion power, a circuit part will handle. All folks have seen that a sixty watts lamp provides less lightweight than a one hundred watts lamp. after we pay invoice for electricity consumption, we tend to are literally paying the charges for power for a specified amount of your time. so power calculation is kind of essential for analyzing an electrical circuit or network.
Power is that the rate of energy provided or consumed by an electrical component with relation to time.
Voltage=IxR
V= Voltage
I= Current
R= Resister
Suppose, part provides or consumes associate degree energy of dw joules for a time of a second, then power of the part may be portrayed as,
also written as
So, the ability of a circuit part is that the product of voltage across the part and current through it. As we've already told that a circuit part will either absorb or deliver power. we have a tendency to represent the absorption of power by golf stroke a positive sign (+) within the expression of power. Likewise, we have a tendency to place a negative sign (-) after we represent the ability delivered by the circuit part.
Passive Sign Convention
There is a straightforward relationship between the direction of current, polarity of voltage and sign of the ability of a circuit part. we have a tendency to decision this easy relationship as passive sign convention. once a current enters in a part through its terminal of positive voltage polarity, we have a tendency to place a positive sign (+) before the merchandise of the voltage and current. this suggests that the part absorbs or consumes power from the electrical circuit. On the opposite hand, once the present through the part leaves its terminal of positive voltage polarity, we have a tendency to place a negative sign (-) before the merchandise of the voltage and current. this suggests that the part delivers or provides power to the electrical circuit.
Let us take an electrical device connected to 2 circuit terminals. Although, the remainder of the circuit isn't shown here in the figure. The polarity of the free fall of the electrical device and also the direction of current through the electrical device are shown in the figure below. The electrical device is intense an influence of vi watts as current I ampere enters within the electrical device although its positive aspect of the born Vage v volt, as shown.
Let us take electric battery connected across 2 circuit terminals. Although, the remainder of the circuit isn't shown here in the figure. The polarity of the dip across the battery and also the direction of current through the battery area unit shown in the figure below. The battery is delivering an influence of vi watts as current I ampere enters within the battery of v V through its positive polarity terminal as shown.
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