1. Analog vs Digital Signal

1.1 Analog Signals 
 Analog signals are signals that are continuous — meaning their values can change smoothly without jumps, representing physical quantities from the real world such as temperature, light, sound, and pressure. 
 Characteristics of analog signals: 
 
 Values can be any real value within a range. 
 Sensitive to noise (electromagnetic interference, heat, etc.). 
 Interact directly with the real world (sensors, microphones, photodiodes). 
 
 
 1.2 Digital Signals 
 Digital signals are signals that are discrete — their values can only be in two conditions: HIGH (1) or LOW (0), usually in the form of a square wave . 
 Characteristics of digital signals: 
 
 Only have two values : 0 and 1 (LOW and HIGH). 
 Nearly immune to noise . 
 Used in data transmission and processing within electronic devices. 
 Use less energy. 
 
 
 1.3 Comparison of Analog and Digital 
 
 
 
 Aspect 
 Analog Signal 
 Digital Signal 
 
 
 
 
 Nature 
 Continuous 
 Discrete 
 
 
 Values 
 All real values 
 0 or 1 
 
 
 Noise Resistance 
 Low 
 Very high 
 
 
 Primary Use 
 Sensors, real-world actuators 
 Data processing, computing 
 
 
 Examples 
 Microphone sound, LDR output, sensor temperature 
 Serial data, clock signals, PWM 
 
 
 Energy Consumption 
 Relatively larger 
 More efficient 
 
 
 
 Both complement each other: analog signals capture real-world phenomena accurately, then are converted to digital so they can be processed by computers/microcontrollers.