Sensor Types and Applications

10 cards

Explores various sensor types such as light, temperature, displacement, strain, magnetic field, and current sensors, along with their applications and underlying physics.

10 cards

Review

Spaced repetition shows you each card at the optimal time for long-term memorization, with increasingly spaced reviews.

Question

What is the primary characteristic of an undoped silicon crystal at 0K?

Answer

At 0K, an undoped silicon crystal behaves as an insulator due to all valence electrons being locked in covalent bonds.

Question

How does doping silicon with Arsenic (As) change its conductivity?

Answer

Doping silicon with Arsenic (valence 5) creates n-type silicon with excess free electrons, increasing its conductivity.

Question

What is a 'hole' in p-doped silicon?

Answer

A 'hole' is the absence of an electron in a covalent bond in p-doped silicon, acting as a positive charge carrier.

Question

What happens in a PN junction when it is non-polarized?

Answer

In a non-polarized PN junction, diffusion creates an internal electric field and a potential barrier (Vi) that stops further charge flow.

Question

When is a PN junction diode considered 'blocked'?

Answer

A PN junction diode is 'blocked' when reverse biased (V0 < 0), meaning no significant current flows as the potential barrier is increased.

Question

What is the threshold voltage for a typical 1N4148 diode?

Answer

The threshold voltage for a typical 1N4148 diode is approximately 0.6V, meaning it conducts when forward biased above this voltage.

Question

What is the main function of a half-wave rectifier?

Answer

A half-wave rectifier selectively allows only one-half of an AC waveform to pass, converting AC to pulsating DC.

Question

How does a LED emit light?

Answer

A LED emits light when an electron recombines with a hole, releasing energy as photons (hν) through its transparent envelope.

Question

In a photodiode, what causes the current to flow from P to N when photons arrive?

Answer

Photons provide energy, moving electrons from the valence to the conduction band, which are then driven by the electric field (Ei) from P to N.

Question

What is a primary application of the 4th quadrant operation of a photodiode?

Answer

The 4th quadrant operation of a photodiode is primarily used in solar panels to generate electrical power from light.

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