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anigeo
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Why is the potential difference across a conducting diode zero?
Potential difference across a diode
- Thread starter anigeo
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In summary, the potential difference across a conducting diode is not zero. Although this is convenient for thinking about switches and voltages, it is not the case in digital circuitry.
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dlgoff
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If the potential difference across a diode in zero, it's not conducting.
Looks like there's a nonzero voltage everywhere except when the current is zero.
Unless of course it's shorted internally. But even then, you'll see a potential difference, albeit kinda small.
Looks like there's a nonzero voltage everywhere except when the current is zero.
Unless of course it's shorted internally. But even then, you'll see a potential difference, albeit kinda small.
- #3
anigeo
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but then in explaining the working of the signal circuits of the OR and AND gates , i found the book assuming that there can be no potential difference across a diode
Pls refer to this youtube video from one of the best EEC professors in india(He says the same)
I shall wait for your reply.
Thank you.
Pls refer to this youtube video from one of the best EEC professors in india(He says the same)
I shall wait for your reply.
Thank you.
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- #4
NascentOxygen
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The PD is small and approximately constant over a range of forward currents. In comparison with other voltages around the circuit, it is often convenient to think of it as 0 volts. (We may approximate 0.6V to 0 volts, especially when discussing applications where the difference does not matter. Alternatively, you can picture the discussion as involving idealized diodes.)anigeo said:
It is usually convenient to think of a mechanical switch as having zero volts across it when it is in the ON position, though we all recognize that no practical switch can have 0.000000V across its contacts while conducting useful lighting current in the home.
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sophiecentaur
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anigeo said:
This is the world of Real Engineering, in which insignificant quantities can be validly regarded as zero. If the circuitry that follows a diode is not 'aware' that it isn't zero (when it is near zero) then it IS zero. In digital circuitry, we use 0 and 1 quite happily when neither of those voltage levels is actually 0 or 1.
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- #6
dlgoff
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sophiecentaur said:
I'm thinking that since this is a "Lecture Series on Electronics For Analog Signal Processing", the OP will need to understand the diode curve sooner or later.
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sophiecentaur
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dlgoff said:I'm thinking that since this is a "Lecture Series on Electronics For Analog Signal Processing", the OP will need to understand the diode curve sooner or later.
Oh yes, I agree but the link he gives in which the zero voltage drop statement is made is a lecture on diodes being used in logic circuits. He is taking what the teacher said, out of context.
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dlgoff
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Yea. I wish he/she would have given a link to the lecture on his/her first post. Just trying to justify my response to it.sophiecentaur said:
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FAQ: Potential difference across a diode
What is potential difference across a diode?
The potential difference across a diode, also known as the forward voltage, is the amount of voltage required to overcome the barrier potential and allow current to flow through the diode in the forward direction.
What is the significance of potential difference across a diode?
The potential difference across a diode is important because it determines whether the diode will be in a state of forward or reverse bias. In forward bias, the diode allows current to flow, while in reverse bias, the diode blocks the flow of current.
How is potential difference across a diode measured?
Potential difference across a diode can be measured using a voltmeter. The positive lead of the voltmeter is connected to the anode of the diode, and the negative lead is connected to the cathode. The reading on the voltmeter will give the potential difference across the diode.
What factors affect the potential difference across a diode?
The potential difference across a diode can be affected by temperature, current, and the type of material used to make the diode. Higher temperatures can increase the potential difference, while higher currents can decrease it. Different materials have different barrier potentials, which can also affect the potential difference.
What happens if the potential difference across a diode is too high?
If the potential difference across a diode is too high, it can cause the diode to break down and allow a large amount of current to flow through it. This can lead to overheating and damage to the diode. It is important to use proper circuit design and voltage regulation to prevent this from happening.