Control & instrumentation
Digital Electronics
5 self-contained study topics — notes, diagrams, formulas, and worked examples for exams and GATE.
Topics
- Boolean AlgebraBoolean algebra manipulates logic expressions using theorems like De Morgan’s and absorption; the goal is a minimal SOP or POS form, found quickly with a Karnaugh map for up to about six variables.
- Combinational Logic DesignCombinational circuits produce outputs that depend only on the present inputs; standard building blocks — adders, multiplexers, decoders — are combined to realise any Boolean function.
- Sequential Logic DesignSequential circuits have memory: the output depends on the present inputs and the stored state, updated by flip-flops on the clock edge; the characteristic equation of each flip-flop defines its next state.
- A to D and D to A ConvertersA DAC reconstructs an analog voltage from a binary code (weighted sum of bits), while an ADC quantises an analog input into n bits with resolution V_ref/2ⁿ; converter choice trades speed against complexity.
- Memory and Programmable LogicMemory capacity is 2^(address lines) words × data-width bits; the address bus width sets the number of locations, and technology (SRAM, DRAM, ROM, flash) trades speed, density and volatility.