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hover
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Is VI=P strictly an ohmic relation or does it apply to all types of circuits?
Thanks
Thanks
hover said:Is VI=P strictly an ohmic relation or does it apply to all types of circuits?
Thanks
berkeman said:What is the context of the question?
hover said:So it doesn't matter whether the device is ohmic or not?
berkeman said:What do you mean by "ohmic"? Do you mean a power factor = 1?
hover said:I mean does the object have to follow ohms law V=IR?
berkeman said:I'm not trying to be dense here, but I'm still not quite understanding. Do you mean where "R" is not a complex impedance? Could you please give an example of something that doesn't "follow Ohm's Law"? Thanks.
hover said:Something like a light bulb. As the voltage increases, the resistance the lightbulb has isn't linear.
berkeman said:Ah. The resistance of the filimant varies with temperature (this is true of most conductors BTW). It doesn't vary with voltage, per se. A higher voltage causes a larger current to flow, which heats up the filament more, which changes its resistance. V=IR is true at any moment in time, even during the transients like at turn on or if you increase the voltage once the bulb is on.
Do you have another example of what you would consider non-Ohmic?
hover said:That was basically it. So I'm guessing that VI=R does work for something like a light bulb right?
berkeman said:Yes, absolutely.
For circuits that have reactive devices like inductors and capacitors, the simple linear V=IR Ohm's Law equation is extended to include complex impedances. The equation still works, but "R" --> Z where Z is a complex number.
An ohmic relation refers to the relationship between voltage (V) and current (I) in a circuit, where the current is directly proportional to the voltage. This means that as the voltage increases, the current also increases in a linear manner.
An ohmic relation follows Ohm's Law, where the resistance remains constant and the current is directly proportional to the voltage. In a non-ohmic relation, the resistance changes with the voltage, resulting in a non-linear relationship between voltage and current.
No, VI=P is not strictly an ohmic relation for all materials. Some materials, such as semiconductors, have non-linear relationships between voltage and current due to their varying resistance at different voltages.
To determine if a material follows an ohmic relation, you can plot a graph of voltage versus current. If the graph is a straight line passing through the origin, then the material follows an ohmic relation. If the graph is curved, then the material has a non-ohmic behavior.
Understanding ohmic and non-ohmic relations is important in designing and analyzing electronic circuits. Ohmic materials are used to control the flow of current in a circuit, while non-ohmic materials can be used to create specific effects, such as diodes and transistors. It is also important to understand these relationships in order to troubleshoot and solve problems in circuits.