Tools : Various types of tools are shown to understand Fuses and Fuse Holders :Various types of fuses are discussed elaborately. Fuse holders and sockets are shown. Electronic components: Resistor, capacitor, Inductance, Transformer, Diode, LED, Opto-coupler, UJT, Bridge Rectifier, Diac, Zener Diode, Schottky Diode, Thermistor, Transistors, FET, JFET, MOSFET, IGBT, LDR, SCR, Triac, IC 555. Are discussed with color pictures and example circuit are shown. Various Power Supplies : Various power supplies are discussed with color pictures. Operational Amplifiers: All types of Operational amplifiers and its uses are discussed. Digital ICs: Various digital ICs are discussed with truth table. ADC and DAC are mentioned. Microprocessor: 8085 Microprocessor pin number and its pneumonics are discussed with examples. Micro Controllers and Arduino : Micro controller’s architecture is explained. Arduino’s IDE is explained and examples are discussed elaborately. ATMEL: Architecture with pneumonic are mentioned to use. Raspberry Pi: Its use of languages and IDEs are discussed. Example programs are written with Python language.