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Diodes do not obey Ohm's Law, at least when viewed as an individual component. When doing circuit analysis, however, you can make the case that, for a specific situation, they do. In fact, using this technique, everything "obeys" Ohm's law.
In the simple case of a resistor, operated within its limits, Ohm's Law works just fine. Voltage is current times resistance. As voltage goes up, current goes up proportionately. You can predict the voltage or current knowing the other along with resistance.
A diode, on the other hand, is non linear. As you apply voltage across it in the forward direction, it initially has high resistance. All of a sudden it has low resistance as it begins to conduct. As you increase the current, the resistance decreases, so the voltage drop is relatively (though not exactly) constant. At a certain point, around when you exceed the maximum forward current, the diode fails.
In the reverse direction, an ordinary diode seems to have high resistance, until you reach about max reverse voltage, at which point the diode fails. In the case of a zener diode, reverse behavior is similar to forward behavior, except at a different voltage.
Even though the diode does not obey Ohm's law, you can still use Ohm's Law to analyze the circuit. You just have to remember that the dynamic resistance of the diode changes as a function of the applied voltage. The value of Ohm's Law becomes evident when you consider that, at each static condition of the circuit, you do know the voltage and current through the diode and, as a result, you can use Ohm's law to calculate its dynamic resistance. This will allow you to extend the analysis by back substitution and simplification until you know more and more about the circuit.
Wiki User
∙ 13y ago
Wiki User
∙ 11y agoYes. The peculiar part is that a diode's resistance changes, depending on the voltage across it. But the relationship among E, I, and R is still valid.
AnswerNo. For a circuit or device to obey Ohm's Law, the ratio of voltage to current must remain constant for changes in voltage. This does not happen with a diode, therefore, a diode does not obey Ohm's Law! However, the ratio of voltage to current will indicate what the resistance happens to be for that particular ratio whether a device obeys Ohm's Law or not. The equation R = V/I does NOT represent Ohm's Law, it is derived from the definition of the ohm.
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How do conductors obey the Ohm's law?
Very few conductors obey Ohm's Law, and its the rise in temperature of the conductor when current flows though it that prevents it from obeying Ohm's Law. Some alloys, such as constantan, obey Ohm's Law over a limited range because, over that range, changes in temperature don't affect their resistance. It's really time that we stopped teaching Ohm's Law, as it is not universal, and applies to very few conductors and hardly any electronic components!
What is a linear resistor?
which obey ohms law ANSWER: Not all potentiometers are linear some are made to follow a logarithm function some follows an exponential function. A linear potentiometer will have a linear curve. Materials that obey Ohm's Law are called 'linear' or 'ohmic'; those that don't are called 'non-ohmic' or 'non-linear'.
How vacuum tubes do not obey ohms law in circuit design?
In point of fact, vacuum tubes do obey Ohm's law. Everything electrical obeys Ohm's law. The reason vacuum tubes don't appear to obey the law is that not every consideration takes into account the fact that vacuum tubs have dynamicresistance. Ohm's law, as applied to "pure" ohmic resistors, requires constant resistance, which no material, no matter how good, exhibits. In the real world, you have to consider that resistance can vary along with voltage and current, and this "complicates" things.
Is diode ohmic or non-ohmic conductor?
Diode is a non-ohmic conductor since in diodes current-voltage relation ship does't obey Ohm's law....the relationship between current and voltage is nonlinear here,...
What does the i stand for in ohms law?
Current
Do pure semiconductor obey ohms law?
No semiconductor's do not obey ohm's laws.
When does a thermostor obey ohm's law?
I hope you mean the thermistor. If so,well it does not obey Ohms law. When current flows through the thermistor its temperature start increasing which reduces the resistance of the thermistor. A reduction in resistance at the same supply voltage will cause the current to increase. Thus it's not obeying Ohms law.
Why does ohm's matter with speakers?
the vibration produced in the coil of a speaker is due to current passing through it hence it obey ohms law
How do conductors obey the Ohm's law?
Very few conductors obey Ohm's Law, and its the rise in temperature of the conductor when current flows though it that prevents it from obeying Ohm's Law. Some alloys, such as constantan, obey Ohm's Law over a limited range because, over that range, changes in temperature don't affect their resistance. It's really time that we stopped teaching Ohm's Law, as it is not universal, and applies to very few conductors and hardly any electronic components!
How do you calculate 1.67 ohms?
ohms law.
According to ohms law what is the resistance of a light if the voltage is 9.0 volts and the current is 0.30 amps?
30 ohmsAnswerAn incandescent lamp doesn't obey Ohm's Law, because the ratio of voltage to current changes as the supply voltage is varied. All you can say is that, when the applied voltage is 9.0 V, then the resistance will happen to be 30 ohms. If you change the applied voltage to some other value, then you will find the resistance will have changed too. Ohm's Law isn't a universal law; in fact, most materials and circuit devices do not obey Ohm's Law, and tungsten, from which lamp filaments are manufactured, is an example of a metal that does not obey Ohm's Law (we call them 'non-linear' or 'non-ohmic')
What is a linear resistor?
which obey ohms law ANSWER: Not all potentiometers are linear some are made to follow a logarithm function some follows an exponential function. A linear potentiometer will have a linear curve. Materials that obey Ohm's Law are called 'linear' or 'ohmic'; those that don't are called 'non-ohmic' or 'non-linear'.
How vacuum tubes do not obey ohms law in circuit design?
In point of fact, vacuum tubes do obey Ohm's law. Everything electrical obeys Ohm's law. The reason vacuum tubes don't appear to obey the law is that not every consideration takes into account the fact that vacuum tubs have dynamicresistance. Ohm's law, as applied to "pure" ohmic resistors, requires constant resistance, which no material, no matter how good, exhibits. In the real world, you have to consider that resistance can vary along with voltage and current, and this "complicates" things.
When was Obey The Law created?
Obey The Law was created on 1926-11-05.
How do you find conductance using ohms law?
To find the conductance using ohms law,you take the inverse of the resistance(/R)
How V equals IR in ohms law?
It doesn't! Ohm's Law simply states that for a limited range of conductors, the ratio of voltage to current is constant for variations in voltage. No mention of resistance. And Ohm's Law only applies to a relatively-small number of conductors; most materials and electrical devices such as diodes, etc., simply do no obey Ohm's Law. Those that do are called 'linear' or 'ohmic' materials or devices; those that don't are called 'non-linear' or 'non-ohmic'.The equation, V = IR (or, more specifically, R = V/I ) comes from the definition of the ohm, and NOT from Ohm's Law.
Is diode ohmic or non-ohmic conductor?
Diode is a non-ohmic conductor since in diodes current-voltage relation ship does't obey Ohm's law....the relationship between current and voltage is nonlinear here,...
