In ns = V / R, present is straight Proportional to the Voltage, but Current is Inversely Proportional to the Voltage in ns = VI?

This is one more confusing question greatly asked in electrical and electronics engineering interviews as is follow.

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According come Ohm’s Law, Current rises when Voltage increases (I=V/R), but Current decreases as soon as Voltage increases follow to (P = VI) formula. Just how do you explain?


According to Ohm’s Law: i ∝ V (Current straight proportional come the Voltage. I = V/R)According to power Formula: i ∝ 1/V (Current is inversely proportional come the Voltage. I = P/V)

In short, follow to the Ohm’s regulation (V = IR or ns = V/R) which reflects that current is straight proportional come the Voltage, yet according come P=VI or I=P/V, it reflects that existing is inversely proportional to the Voltage.


Let’s clean the confusion around the statement.

P = V x I

Actually, it relies on how you increase the parameters i.e. If you rise the voltage by keeping the power of the source consistent or is that varying.

If the strength of the resource is constant then the present would decrease once voltage increases.If friend don’t care around the power and just simply replace the battery v a brand-new one’s with higher power rating this can increase the current when voltage increase as power is no more continuous i.e. Power has been additionally increased.

In instance of transformer, as soon as voltage boosts then current decrease due to the fact that power remains constant i.e. Both side power is ns = using (neglecting the power factor: Cos θ).

V = i x R

By Ohm’s Law, present (I) is directly proportional to the Voltage (V) if Resistance (R) and also Temperature remain constant. 

V = IRR = V/II = V/R

According the strength formula, It claims that existing is inversely proportional come the voltage if power stay same.

P = V x II = P/VV = P/I

As we already know the in a step-up transformer, if voltage increases, the existing decreases whereby power is exact same (as transformer just step-up or step-down the value of current and also voltage and also doesn’t readjust the value of power). Similarly, voltage to reduce when present increases in a step-down transformer.

The very same story is over there at the generating station where strength generation is constant. If power at generation next improves, both current and voltage will certainly be increased.

In short:

If power is continuous = Voltage is Inversely proportional come the Current i.e V ∝ 1/I in P = VxI.If resistance and also Temperature is constant: Voltage is directly proportional come the Current i.e. V ∝ I in V = IxR.

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That’s is the exact reason why in Ohm’s Law, present is straight Proportional to the Voltage but Inversely Proportional to the Voltage in power formula.