A. Logic Gate In the field of Electronics, logic gatespertain to devices whose main function is to perform Boolean functions, such asOR and AND. More specifically, logic gates take one or more binary inputs anddo a logical operation on them to produce a single binary output 1. A Boolean function utilizes the binarynumber system, meaning, it only involves the numbers 1 and 0. Normally, 1 isassigned as “Truth” while 0 is assigned as “False”. Different operations areperformed using these digits and the most commonly used ones are OR, AND, andNOT.
An OR function takes two or more inputs and produces an output of 1 ifthere is at least one input of 1. On the other hand, an AND function only givesan output of 1 if none of the inputs are 0. Lastly, a NOT function just invertswhatever it receives: if the input is 1, the output is 0 and vice versa.Additionally, a Truth Table is also often used to show the possible outcomes ofa function. An example of a Truth Table for an OR function is shown in figure1. Fig.
1. OR Function Truth Table. Logic gates perform these Booleanfunctions using electronic switches such as diodes and transistors. Throughthese switches, the output of the circuit can be manipulated to imitate ordemonstrate expected outcomes of Boolean functions. This laboratory will verifythis through simple circuits involving diodes and transistors.B.
Diodes in Logic GatesA semiconductor diode is made by connecting two crystal ofsemiconductors which are usually made of silicon (most common), germanium andgallium arsenide. A process called doping is done by adding impurities (otherelements) to these semiconductor crystals to create regions that has charges,positive and negative 2. Moreover, the process of attachment of these twotypes of semiconductor creates a momentary flow of electrons from the n region(region of negative charges) to p region (region of positive charges), making athird region where no charge carriers are present.
This region is called thedepletion region that stops the natural flow of electrons and stabilizes thecurrent in the diode. The diode’s terminal are placed to the n-type and p-typeregions as shown in figure 2.