Electronics fundamentals, common ICs, PLC programming (IEC 61131-3), mechatronics.
Fundamental Laws
| Law | Formula | Description |
|---|---|---|
| Ohm's Law | V = I·R | Voltage = Current × Resistance |
| Power | P = V·I = I²R = V²/R | Electrical power (watts) |
| Kirchhoff's Current Law (KCL) | ΣI_in = ΣI_out | Sum of currents at node = 0 |
| Kirchhoff's Voltage Law (KVL) | ΣV = 0 around loop | Sum of voltages in closed loop = 0 |
| Capacitor charge | Q = C·V | Charge stored |
| Capacitor energy | E = ½CV² | Energy stored |
| Inductor voltage | V = L·(dI/dt) | Voltage across inductor |
| RC time constant | τ = R·C | 63.2% charge/discharge time |
| RL time constant | τ = L/R | 63.2% current rise time |
| Resonant frequency | f = 1/(2π√LC) | LC circuit resonance |
Common Passive Components
| Component | Symbol | Unit | Key Parameter |
|---|---|---|---|
| Resistor | R | Ω (ohm) | Resistance, power rating (W), tolerance (%) |
| Capacitor | C | F (farad) | Capacitance, voltage rating, type (ceramic/electrolytic/film) |
| Inductor | L | H (henry) | Inductance, current rating, DCR |
| Transformer | T | — (ratio) | Turns ratio n=Vp/Vs, isolation, VA rating |
| Diode | D | — | Forward voltage Vf, Imax, reverse voltage Vr |
| Zener diode | D_Z | — | Breakdown voltage (regulation), power rating |
| Fuse | F | A | Current rating, breaking capacity, response time |
Common ICs
| IC | Type | Description |
|---|---|---|
| NE555 | Timer | Monostable/astable oscillator, PWM, delays — ubiquitous |
| LM741 | Op-amp | Classic general-purpose operational amplifier |
| LM358 | Op-amp | Dual op-amp, single-supply, low power |
| LM7805 | Regulator | 5V fixed linear regulator (1A) |
| LM317 | Regulator | Adjustable linear regulator 1.25V–37V |
| ATmega328P | MCU | Arduino Uno core, 8-bit AVR, 32KB flash |
| STM32F103 | MCU | 32-bit ARM Cortex-M3, 72MHz, popular dev board |
| ESP32 | MCU+WiFi+BT | Dual-core Xtensa, WiFi, Bluetooth, IoT standard |
| Raspberry Pi RP2040 | MCU | Dual Cortex-M0+, 264KB SRAM, PIO |
| L298N | H-bridge | Dual H-bridge motor driver, 2A per channel |
| ULN2003 | Driver | 7-channel Darlington driver for relays/steppers |
| MAX232 | Level shifter | RS-232 ↔ TTL level conversion |
| PCF8574 | I/O expander | 8-bit I²C GPIO expander |
PLC Programming (IEC 61131-3)
| Language | Type | Description | Best For |
|---|---|---|---|
| Ladder Diagram (LD) | Graphical | Relay logic graphical notation — contacts + coils | Simple relay replacement, sequencing |
| Function Block Diagram (FBD) | Graphical | Blocks connected by data flow lines | Analog control, PID, complex logic |
| Structured Text (ST) | Textual | Pascal-like high-level language | Complex algorithms, math, strings |
| Instruction List (IL) | Textual | Assembly-like mnemonics (deprecated in IEC 61131-3 ed.3) | Legacy systems |
| Sequential Function Chart (SFC) | Graphical | State machine with steps + transitions | Sequential processes, batch control |
PLC Hardware
| Component | Description |
|---|---|
| CPU module | Executes ladder/ST program, scan cycle typically 1–100ms |
| Digital Input (DI) | Reads discrete signals (24VDC, 230VAC) — switches, sensors |
| Digital Output (DO) | Drives discrete loads — relays, solenoids, indicator lights |
| Analog Input (AI) | Reads 4–20mA or 0–10V signals — temperature, pressure, level |
| Analog Output (AO) | Outputs 4–20mA / 0–10V — drives VFDs, control valves |
| Communication | Profibus, Profinet, EtherNet/IP, Modbus RTU/TCP, CANopen |
| HMI / SCADA | Operator interface; SCADA monitors multiple PLCs remotely |
| VFD (Variable Frequency Drive) | Controls AC motor speed via frequency/voltage adjustment |
Mechatronics Integration
| System | Components | Key Protocols |
|---|---|---|
| CNC Machine | PLC/Motion controller + servo drives + encoders + G-code | EtherCAT, SERCOS |
| Industrial Robot | Controller + servo joints + vision + force sensor | EtherCAT, DeviceNet |
| Conveyor Line | PLC + VFDs + sensors + HMI | Profinet, Modbus |
| HVAC Control | BMS + temperature/humidity sensors + actuators + PLC | BACnet, Modbus, KNX |
| Smart Factory (Industry 4.0) | Edge computing + IoT sensors + cloud SCADA + AI analytics | OPC-UA, MQTT, REST |
