Podcast
Questions and Answers
What is the color of the positively charged side of the junction's depletion region?
What is the color of the positively charged side of the junction's depletion region?
- Blue
- Green
- Red (correct)
- Yellow
What type of bias is represented in the region where the current is nearly zero?
What type of bias is represented in the region where the current is nearly zero?
- Forward bias
- Total bias
- Zero bias
- Reverse bias (correct)
Which diagram correctly represents reverse bias?
Which diagram correctly represents reverse bias?
- Neutral bias diagram
- Zero bias diagram
- Reverse bias diagram (correct)
- Forward bias diagram
What does the term 'bias' mean in the context of a PN junction?
What does the term 'bias' mean in the context of a PN junction?
What is the result of forward biasing a PN junction?
What is the result of forward biasing a PN junction?
What is the depletion region of a PN junction?
What is the depletion region of a PN junction?
What happens to the depletion region during forward bias?
What happens to the depletion region during forward bias?
What is the energy required for electrons to pass through the depletion region equal to?
What is the energy required for electrons to pass through the depletion region equal to?
What is the result of the energy loss when electrons cross the depletion region?
What is the result of the energy loss when electrons cross the depletion region?
What is the effect of the internal resistance of the material on the voltage drop?
What is the effect of the internal resistance of the material on the voltage drop?
What is the purpose of reverse biasing a diode?
What is the purpose of reverse biasing a diode?
What happens to the depletion region during reverse bias?
What happens to the depletion region during reverse bias?
What happens to the majority carriers in the n region during reverse bias?
What happens to the majority carriers in the n region during reverse bias?
What happens in the p region during reverse bias?
What happens in the p region during reverse bias?
What happens to the depletion region when a reverse-bias voltage is applied?
What happens to the depletion region when a reverse-bias voltage is applied?
What is the characteristic of the initial flow of charge carriers when a reverse-bias voltage is applied?
What is the characteristic of the initial flow of charge carriers when a reverse-bias voltage is applied?
What happens to the reverse current when the external reverse-bias voltage is increased to a certain value?
What happens to the reverse current when the external reverse-bias voltage is increased to a certain value?
What is the current that flows when a forward bias is applied across a diode?
What is the current that flows when a forward bias is applied across a diode?
What happens to the forward current when the forward-bias voltage exceeds the diode's internal barrier voltage?
What happens to the forward current when the forward-bias voltage exceeds the diode's internal barrier voltage?
What is the characteristic of the I-V curve for a diode in forward bias?
What is the characteristic of the I-V curve for a diode in forward bias?
What is the characteristic of a diode when it is reverse-biased?
What is the characteristic of a diode when it is reverse-biased?
What is the internal barrier voltage of a silicon diode?
What is the internal barrier voltage of a silicon diode?
What is the direction of the diffusion current ID?
What is the direction of the diffusion current ID?
What happens to the holes that diffuse across the junction into the n region?
What happens to the holes that diffuse across the junction into the n region?
What is the result of the recombination process in the p region?
What is the result of the recombination process in the p region?
What is the purpose of the built-in potential barrier across the PN junction?
What is the purpose of the built-in potential barrier across the PN junction?
What is the effect of applying a suitable positive voltage (forward bias) between the two ends of the PN junction?
What is the effect of applying a suitable positive voltage (forward bias) between the two ends of the PN junction?
What is the term for the current component due to electrons diffusing across the junction from the n side to the p side?
What is the term for the current component due to electrons diffusing across the junction from the n side to the p side?
What is the region close to the junction that is depleted of free electrons called?
What is the region close to the junction that is depleted of free electrons called?
What happens to the free electrons that disappear from the n-type material due to recombination?
What happens to the free electrons that disappear from the n-type material due to recombination?
What happens when the reverse voltage across the diode becomes greater than its breakdown voltage point?
What happens when the reverse voltage across the diode becomes greater than its breakdown voltage point?
What is the primary reason for the choice of the arrow-like circuit symbol for a diode?
What is the primary reason for the choice of the arrow-like circuit symbol for a diode?
What is the ideal behavior of a forward-biased diode?
What is the ideal behavior of a forward-biased diode?
What happens when a diode is reverse-biased and the reverse bias voltage doesn't exceed the breakdown voltage of the junction?
What happens when a diode is reverse-biased and the reverse bias voltage doesn't exceed the breakdown voltage of the junction?
What is the characteristic curve of a diode when the reverse voltage exceeds the breakdown voltage point?
What is the characteristic curve of a diode when the reverse voltage exceeds the breakdown voltage point?
What is the primary function of an ideal diode in a circuit?
What is the primary function of an ideal diode in a circuit?
What is the term used to describe a forward-biased diode?
What is the term used to describe a forward-biased diode?
What is the main difference between a forward-biased and reverse-biased diode?
What is the main difference between a forward-biased and reverse-biased diode?
Study Notes
Operation with Open-Circuit Terminals
- Holes diffuse across the junction from the p side to the n side, while electrons diffuse across the junction from the n side to the p side, forming the diffusion current ID.
- The direction of ID is from the p side to the n side.
Depletion Region
- Holes that diffuse into the n region recombine with majority electrons, resulting in a region close to the junction depleted of free electrons.
- Similarly, electrons that diffuse into the p region recombine with majority holes, resulting in a region close to the junction depleted of free holes.
Barrier Potential across PN Junction
- A potential barrier exists across the junction, opposing the flow of holes and electrons.
- The barrier potential is the energy required for electrons to pass through the depletion region.
Forward Bias
- A suitable positive voltage (forward bias) applied between the two ends of the PN junction supplies free electrons and holes with extra energy, reducing the depletion region.
- During forward bias, the energy loss results in a voltage drop across the PN junction equal to the barrier potential (0.7 V).
Reverse Bias
- Reverse bias essentially prevents current through the diode.
- Unlike charges attract, pulling majority carriers away from the PN junction, widening the depletion region and depleting majority carriers.
- The reverse current is very small and can usually be neglected, but will drastically increase if the external reverse-bias voltage exceeds the breakdown voltage.
V-I Characteristic for Forward Bias
- When forward bias is applied, the forward current and voltage across the diode gradually increase.
- The curve increases gradually into the forward quadrant, but the forward current and voltage are extremely small until the forward voltage exceeds the diode's internal barrier voltage (0.7 V), at which point the forward current increases rapidly.
V-I Characteristic for Reverse Bias
- The diode blocks current except for an extremely small leakage current, operating in the lower left quadrant of its I-V characteristic curves.
- The diode continues to block current flow until the reverse voltage becomes greater than its breakdown voltage point.
Diode Models
- Ideal diode model: conducts in one direction and not in the other.
- Practical diode model: includes internal resistance and barrier potential.
- Complete diode model: includes internal resistance, barrier potential, and breakdown voltage.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about the diffusion current in semiconductor junctions, including the movement of holes and electrons across the p-n junction.
