Is Ohm's Law applicable for only DC or for both?

In summary, Ohm's law (V = IR) is valid for both AC and DC circuits, but the actual expression used for AC is J = sigma * E, where J is current density, sigma is conductivity, and E is electric field. For DC, the formula P = VI = V^2/R = I^2*R can be used, while for AC, the formula P = VIcos is used. The difference lies in the expressions for resistance and impedance, with R being used for DC and Z (where Z = R + jX) being used for AC.
  • #1
Usama Khurram
9
0
Is ohm's law (V=IR) works for both AC and DC. PLz explain in details

Also let me know which formula is right for power calculation for AC and DC circuits. (P=VI or P=VICos)
 
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  • #2
ohms law is valid for both ac and dc . but the v=ir form is not actually the ohms law . this form is only valid for dc .
in AC we use the actual expression ..
J=sigma*E
J is current density
sigma is conductivity
E is electrif field

for dc p=vi=v^2/r=i^2*r can be used
the other one mentioned by you is for ac.proton007007
 
  • #3
dc: V = I*R, R = resistance
ac: V = I*Z, where Z = R + jX, X = reactance, Z = impedance

Claude
 
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1. Is Ohm's Law applicable for only DC or for both?

Ohm's Law is applicable for both DC (direct current) and AC (alternating current) circuits. However, it is important to note that Ohm's Law applies only to linear circuits, where the relationship between voltage and current remains constant.

2. Can Ohm's Law be used for all types of resistors?

Yes, Ohm's Law can be used for all types of resistors as long as the circuit is linear. This means that the resistance of the resistor remains constant regardless of the voltage or current applied.

3. How do I calculate voltage, current, or resistance using Ohm's Law?

To calculate voltage (V), current (I), or resistance (R), you can use the formula V = IR, I = V/R, or R = V/I respectively. It is important to use consistent units (e.g. volts, amps, ohms) when plugging in values to ensure accurate calculations.

4. Are there any limitations to Ohm's Law?

Yes, Ohm's Law is only applicable to linear circuits, as mentioned earlier. Additionally, it does not take into account other factors such as temperature or non-idealities in components. In some cases, Ohm's Law may provide an approximate value rather than an exact one.

5. How is Ohm's Law related to other circuit laws and principles?

Ohm's Law is one of the fundamental laws of electricity and is often used in conjunction with other laws and principles, such as Kirchhoff's Laws and the power equation (P = VI). These laws and principles help to explain and predict the behavior of electric circuits.

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