One of the most important and basic building blocks of digital electronics is the NAND gate. Its output is the opposite or the complement of the AND gate, but the NAND gate is considered to be a universal logic gate. A universal logic gate is a gate that can implement any other universal Boolean function. Schmitt Trigger design was used for this specific NAND gate. Schmitt Trigger is a type of circuit invented by Otto H. Schmitt, and it’s a circuit that provides hysteresis to the system circuit using positive feedback that creates different input output thresholds to the circuit. Essentially meaning instead of having one transition threshold, there will be 2 different thresholds which makes our circuit more stable especially for systems where there are noisy signals

The circuit starts with an input stage using 4 clamping diodes to prevent voltage swings when the gate switches from high to low. The signal is then processed by the Schmitt trigger, which eliminates noise and defines transition thresholds using 4 resistors and 2 transistors. Next, the level shifter adjusts the voltage level for circuit compatibility, using 2 resistors, a diode, and a transistor. The signal then reaches the totem-pole output, which either pulls down or pulls up the signal based on the input, and finally drives the LED to indicate the output status.

A strong grasp of electronics fundamentals is crucial for any successful electrical and electronics engineer. Through this project, I not only solidified my understanding of these core principles but also applied them in real-world scenarios. I developed a deep appreciation for how the physical properties of components interact and affect design decisions, guiding a project from initial concept to full implementation. Additionally, I honed my soldering skills, which became a foundational part of my toolkit and allowed me to build on this expertise throughout my career.