Photovoltaic Cells and Solar Energy

Photovoltaic Cell (Solar Cell)

• Converts light into electrical energy
• Photovoltaic effect: sunlight photons knock electrons loose from atoms, generating electricity
• Reduces carbon footprint by harnessing solar energy
• Applications: solar panels, solar-powered chargers, solar street lighting

Photodiode

• Converts photons into electrical current
• Has a similar structure to a normal PN junction diode
• Produces both voltage and current
• Mainly used in solar cells to power electrical equipment from solar energy

Phototransistor

• Amplifies photoelectric current generated from converting light energy
• Has a similar structure to a transistor except for a light-sensitive base region
• Connected only in forward bias, requires a power source to operate
• 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
• Works on the principle of photoconductivity

Laser

• An acronym for "light amplification by stimulated emission of radiation"
• Converts 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

PIR (Passive Infrared) Sensor

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

Hall Effect Sensor

• Transducer that varies its output voltage in response to a magnetic field
• Used for proximity switching, positioning, speed detection, and current sensing applications
• Uses a thin semiconductor with a continuous current
• Deflects charge carriers (electrons and holes) to the sides of the semiconductor, creating a Hall voltage

Proximity Sensor

• A non-contact sensor that detects the presence of an object
• Depending on the type, uses sound, light, infrared radiation (IR), or electromagnetic fields
• Used in phones, recycling plants, self-driving cars, anti-aircraft systems, and assembly lines

Inductive Proximity Sensor

• Detects metallic objects using the electrical principle of inductance
• A fluctuating current induces an electromotive force (EMF) in a target object

Optical Proximity Sensor

• Includes a light source and a sensor that detects the light
• Detects objects directly in front of them by detecting the sensor's own transmitted light reflected back from an object's surface

Capacitive Proximity Sensor

• Can detect both metallic and non-metallic targets in powder, granulate, liquid, and solid form
• Uses the variance in the capacitance of the sensor to conclude that an object has been detected

Magnetic Proximity Sensor

• Detects the presence of a magnetic object
• Sense the presence of a magnetic object, characterized by its magnetic field, triggers the switching process

RF Diode

• Specialized components engineered to manage high-power radio frequency (RF) signals
• Crucial for efficiently controlling and manipulating RF signals, ensuring optimal performance and signal integrity
• Designed to handle high-frequency signals efficiently

Chemical Transducers

• Essential tools that transform chemical information into signals
• Used in food safety, industrial process control, medical diagnostics, and environmental monitoring

Gas Sensors

• Devices that detect the presence or concentration of gases in the atmosphere
• Electromechanical Gas Sensor: an electrochemical cell that quantitatively detects a particular chemical species

Soil Moisture Sensor

• Measures the volumetric water content in the soil
• Sensor mainly utilizes capacitance to gauge the water content of the soil
• Interacts with the water molecules in the soil and changes its capacitance value depending on the amount of water

Humidity Sensor / Hygrometer

• Sensitive electronic devices used to measure the air's humidity
• Divided into two categories: relative humidity sensors and absolute humidity sensors
• Capacitive Humidity Sensor: measures the dielectric material's change in electrical permittivity
• Resistive Humidity Sensor: detects humidity changes by measuring changes in the material's resistivity value

Turbidity Sensor

• Used to quantify the amount of total dissolved/suspended solids in a solution
• Measures the particle concentration and purity of a solution, such as water
• Turbidity is the measure of relative clarity of a liquid

Salinity Sensor

• Used to determine the concentration or refractive index of saline solution by weight
• Measures the conductivity of a solution with a high ion concentration
• Electrode type salinity sensor: operates by immersing two electrodes in the solution, measuring the current flow, and converting it into a salinity value

Learn about photovoltaic cells, also known as solar cells, which convert light into electrical energy, playing a crucial role in sustainable energy and reducing carbon footprint.