Solar Cells and Photodiodes

Photovoltaic Cell (Solar Cell)

• Converts light into electrical energy due to its voltage-producing capability.
• Plays a crucial role in sustainable energy by harnessing solar energy to reduce carbon footprint.
• Works through the Photovoltaic Effect, where sunlight photons knock electrons loose from atoms, generating electricity.
• Applications include solar panels, solar-powered chargers, and solar street lighting.

Photodiode

• A semiconductor device with a P-N junction that converts photons into electrical current.
• Can be used in both forward and reverse bias, producing both voltage and current.
• Mainly used in solar cells to power electrical equipment from solar energy.

Phototransistor

• A light-sensitive transistor that amplifies the photoelectric current generated from converting light energy.
• Has a similar structure to a transistor, except with a light-sensitive base region.
• Connected only in forward bias, requires a power source to operate, and generates current only.
• Mainly used for detecting or sensing light intensity.

LDR (Light Dependent Resistor)

• A tiny light-sensing device also known as a photoresistor.
• Resistance changes as the amount of light falling on it changes, working on the principle of photoconductivity.

Laser

• An acronym for "light amplification by stimulated emission of radiation."
• A special type of diode designed to convert electrical energy into light through stimulated emission.
• Functions similarly to a regular P-N junction, but is optimized for light generation.
• Produces a concentrated, coherent light beam, with the color depending on the type of semiconductor material used.

PIR (Passive Infrared) Sensor

• An electronic sensor used in motion detectors, triggered lighting devices, and protection systems.
• Measures devices emitting infrared light in their field of view, detecting the presence of people or animals through the heat emitted by their bodies.

Hall Effect Sensor

• A transducer that varies its output voltage in response to a magnetic field.
• Used for proximity switching, positioning, speed detection, and current sensing applications.
• Works by deflecting charge carriers (electrons and holes) to the sides of the semiconductor, creating a Hall voltage perpendicular to the current flow and magnetic field.

Ultrasonic Sensor

• An electronic device that measures the distance of a target object by emitting ultrasonic sound waves.
• Converts the reflected sound into an electrical signal, determining the distance by measuring time lapses between the sending and receiving of the ultrasonic pulse.

Magnetometer

• A device that measures magnetic field or magnetic dipole moment.
• Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location.
• Examples include absolute and relative magnetometers, used to measure the Earth's field.

Color Sensor

• Uses photodiodes to convert light reflected from an object into electrical signals.
• Processes the signals to determine the object's color based on its light absorption properties.
• Relies on color models (RGB, CMYK) to translate light information into color data.

Proximity Sensor

• A non-contact sensor that detects the presence of an object (target) when the target enters the sensor's field.
• Uses sound, light, infrared radiation (IR), or electromagnetic fields to detect a target.
• Examples include inductive, optical, capacitive, and magnetic proximity sensors.

E-Nose (Electronic Nose)

• A sensor device that detects smell more effectively than the human sense of smell.
• Used to distinguish complex volatiles that reproduce the structure and principle of olfactory sense.
• Mainly used for quality evaluation, maturity detection, and species identification in fruit and vegetable testing.

Heartbeat Sensor

• A device designed to monitor and measure heart rate in real-time.
• Commonly used in fitness tracking, medical monitoring, and research.
• Detects the pulse by measuring changes in blood volume through the skin using optical or electrical methods.

Breathalyzer

• Operates on the principle that alcohol present in the bloodstream is exhaled in the breath.
• Measures the amount of alcohol vapor present when a person breathes into the device.
• Uses technologies such as fuel cell sensors, semiconductor oxide sensors, and infrared spectroscopy.