Daily review: Voltage Divider Rules | Photodiode…

Q: In a simple voltage divider circuit with two resistors R1 and R2 in series, what is the formula for the voltage across R2 (V_out)?

V_in * (R2 / (R1 + R2)) — The voltage across a resistor in a series string is proportional to its resistance relative to the total circuit resistance.

Q: What is the primary operating mode of a photodiode when used for high-speed light detection applications?

Reverse bias mode — Reverse bias mode reduces junction capacitance, allowing for faster response times in light sensing.

Q: Which of the following is a primary safety purpose of earthing in electrical installations?

To provide a low-impedance path for fault currents to ground — Earthing ensures fault current flows to the ground, triggering protective devices like breakers to prevent electric shock.

Q: If you have a 12V source and two equal resistors (1k? each) in a voltage divider, what is the voltage at the center node?

6V — With equal resistors, the voltage splits exactly in half: 12V * (1k / (1k + 1k)) = 6V.

Q: How does incident light affect the current flowing through a reverse-biased photodiode?

It increases the reverse saturation current proportionally — Photons generate electron-hole pairs in the depletion region, which increases the reverse current flow (photocurrent).

Q: Which grounding practice helps prevent the accumulation of static charge on equipment enclosures?

Equipment earthing — Equipment earthing drains static charges to the earth, preventing potential build-up that could damage sensitive components.

Q: In a voltage divider, what happens to V_out if the load resistor added in parallel to R2 has a very low resistance?

V_out decreases due to loading effects — The effective resistance of the bottom branch decreases, pulling the output voltage lower than the unloaded divider value.

Q: What is the 'dark current' in a photodiode?

The tiny current flowing when there is no incident light — Dark current is the small leakage current that persists in a photodiode even in total darkness.

Q: What is the benefit of using an equipotential bonding strip in an electrical installation?

It ensures all metal parts remain at the same potential during a fault — Equipotential bonding prevents dangerous voltage differences between metal objects during a fault.

Q: Why is the photodiode material usually semiconductor-based?

To enable photon absorption via band-gap energy — Semiconductors have band-gaps that allow photons with sufficient energy to promote electrons, creating an electrical signal.

Question 1 of 10

In a simple voltage divider circuit with two resistors R1 and R2 in series, what is the formula for the voltage across R2 (V_out)?

The voltage across a resistor in a series string is proportional to its resistance relative to the total circuit resistance.

Question 2 of 10

What is the primary operating mode of a photodiode when used for high-speed light detection applications?

Reverse bias mode reduces junction capacitance, allowing for faster response times in light sensing.

Question 3 of 10

Which of the following is a primary safety purpose of earthing in electrical installations?

Earthing ensures fault current flows to the ground, triggering protective devices like breakers to prevent electric shock.

Question 4 of 10

If you have a 12V source and two equal resistors (1k? each) in a voltage divider, what is the voltage at the center node?

With equal resistors, the voltage splits exactly in half: 12V * (1k / (1k + 1k)) = 6V.

Question 5 of 10

How does incident light affect the current flowing through a reverse-biased photodiode?

Photons generate electron-hole pairs in the depletion region, which increases the reverse current flow (photocurrent).

Question 6 of 10

Which grounding practice helps prevent the accumulation of static charge on equipment enclosures?

Equipment earthing drains static charges to the earth, preventing potential build-up that could damage sensitive components.

Question 7 of 10

In a voltage divider, what happens to V_out if the load resistor added in parallel to R2 has a very low resistance?

The effective resistance of the bottom branch decreases, pulling the output voltage lower than the unloaded divider value.

Question 8 of 10

What is the 'dark current' in a photodiode?

Dark current is the small leakage current that persists in a photodiode even in total darkness.

Question 9 of 10

What is the benefit of using an equipotential bonding strip in an electrical installation?

Equipotential bonding prevents dangerous voltage differences between metal objects during a fault.

Question 10 of 10

Why is the photodiode material usually semiconductor-based?

Semiconductors have band-gaps that allow photons with sufficient energy to promote electrons, creating an electrical signal.

Daily review: Voltage Divider Rules | Photodiode | Importance of Earthing Rules in Installations Quiz