FASTEST FINGER PRESS QUIZ BUZZER Project Title FASTEST FINGER PRESS QUIZ BUZZER Under the Guidance of Submitted by

ABSTARCT Manual buzzers used for quiz competitions in schools and colleges create a lot of confusion in identifying the first respondent. It determines the contestant who first presses the switch (S1 through S8) to answer a question and locks out the remaining three entries. Simultaneously, the buzzer and the corresponding led should be ‘on’ after a particular competitor has pressed the pushbutton. The quiz table can be used for up to eight contestants. To design this we using IC 74Ls373 and few passive components.

PROJECT BLOCK DIAGRAM

HARDWARE COMPONENTS 74LS373 unit BC547 PIEZO BUZZER LED’S, Push button POWER SUPPLY BLOCK 74LS373 unit BC547 PIEZO BUZZER LED’S, Push button 1N4007 RESISTORS CAPACITORS

POWER SUPPLY Bridge rectifier 5v Regulator 230 V AC 50 Hz 5V DC Filter(470µf) 12V step down transformer

74LS373 unit The 74LS373 consists of eight latches with 3-state outputs for bus organized system applications. The flip-flops appear transparent to the data (data changes asynchronously) when Latch Enable (LE) is HIGH. When LE is LOW, the data that meets the setup times is latched. Data appears on the bus when the Output Enable (OE) is Low. When OE is HIGH the bus output is in the high impedance state

FEATURES Eight Latches in a Single Package 74LS373 FUNCTIONAL DIAGRAM Eight Latches in a Single Package 3-State Outputs for Bus Interfacing Hysteresis on Latch Enable Edge-Triggered D-Type Inputs Buffered Positive Edge-Triggered Clock Hysteresis on Clock Input to Improve Noise Margin Input Clamp Diodes Limit High Speed Termination Effects

Function Table of 74LS373

BC547(npn transistor) The BC547 transistor is an NPN Epitaxial Silicon Transistor. The BC547 transistor is a general-purpose transistor in small plastic packages. It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors. Whenever base is high, then current starts flowing through base and emitter and after that only current will pass from collector to emitter  

BUZZER Piezo Buzzer This buzzer is an piezo type audio signaling device, which has a piezo element and a oscillating circuit inside which oscillates the piezo brass base plate, which when given voltage difference produces sound of a predefined frequency. Features These high reliability piezo buzzers are applicable to general electronics equipment. Compact, pin terminal type Piezo buzzer with 4 KHz output. Pin type terminal construction enables direct mounting onto printed circuit boards.

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