Telephone Converter Circuit

circuit diagram of telephone converter circuit

A telephone converter circuit that can be used to power the circuit added to the basic phone is shown in figure 1. This may be more economical/convening than adding a separate power supply from the AC power line or using battery power. It takes the -48V provided by the telephone and efficiently converts it to a well-regulated 5V. Circuit Description of Telephone Converter Circuit A telephone converter circuit does not require the bulk and expensive transformer which is usually used in these designs. It takes the -48V (it can function…

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Universal Crystal Test Circuit Using CA4007

circuit diagram of cristal test circuit

Crystal oscillators may fail to operate due to faulty design or faulty crystals. The circuit shown in figure 1 works well as a crystal tester for a wide variety of crystals and ceramic resonators over the 40-kHz to the 20-MHz range. Circuit Description of Universal Crystal Test Circuit Using CA4007 The oscillator in figure 1 is a Pierce type that operates at the crystal’s parallel resonant frequency and presents about 30 pF capacitance to the crystal. The IC1 (CA4007 A) contains three pairs of complementary MOSFETs with the first (input at…

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Sort Circuit Protected Regulated Power Supply Using 741

short circuit protected regulated power supply

Various Power Supply-based projects are already available on bestengineeringprojects.com like short-proof variable power supply, stabilized power supply with short circuit indicator, Universal digital power supply, variable switching power supply, etc. Now here is a straightforward circuit of short circuit-protected regulated power supply utilizing very few components. Circuit Description of Short Circuit Protected Power Supply The electronics project short circuit protected variable power supply utilizing an op-amp 741, two NPN transistors, and a few passive components. Unregulated or fluctuating voltage is first regulated and smoothened by diode D1 and Zener diode ZD1.…

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Electronic Room Thermometer Using Op-amp 741

electronic room thermometer using op amp 741

These days electronic room thermometer is very popular, though it is expensive. Now here we designed a simple and cheap electronic room thermometer using a temperature sensor and op-amp 741. Circuit Description of Electronic Room Thermometer using Op-amp 741 The heart of the circuit electronic room thermometer is IC1 (LM3911), which is used here as a temperature sensor. The output of this IC is variable according to temperature change. Its output increases at the rate of 10mV/0C rise in temperature. At 00C its output is 2.73V. The output from IC1…

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Light Operated lamp switch using DIAC and TRIAC

light operated on off switch without ic

Various electronic projects using LDR (Light Operated Resistor) are already posted on bestengineeringprojects.com. Now, here is another simple project using LDR called a light-operated lamp switch using DIAC and TRIAC. This circuit utilizes very few components and is so simple that anyone can understand it. Circuit Description of Light Operated Lamp Switch: The circuit of light operated lamp switch utilizes a diac and a triac as semiconductors and LDR as a sensor. LDR is a type of variable resistor that changes its value according to the intensity of light falling…

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A Phone Book Application Using C

Phone book Application using C is a simple application that incorporated most of the features of C. I had discussed each of the features of this application between the code, although most of the code has comments. The phone book application provides features like storing a room/phone number into a database, sorting and finding the room number/phone number, etc. This phone book application uses the graphic library for interaction with users. This application can store up to five hundred entries but is not limited to it, user can increase and…

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Employee Management System Using C

menu of Employee Management System Using C

The project employee management system using C manages employee records using the file system. this help to register employee, display all list of an employee on the screen, search a  particular employee record, modify and delete information of an employee. The best part of this project is it uses graphics to more look like real software designed in other higher-level programming languages. So before starting to look for code let’s see the output of the project Employee Management System Using C. This project is compiled using Turbo C++. Figure 1:…

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Analog and Digital Clock Using C

The project aims at developing an analog and digital clock using the C language that displays an analog and as well as a digital clock. Features of clock using C Graphical clock for better visual appearance Beep sound with dedicated time interval Dedicated function for dedicated work like beep, draw line and frame. The code of Analog and digital clocks is written in TurboC++ environment and may not be supported by other various compilers like DEV C, codeBlock, etc. The source code of the application Analog and Digital clock using…

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Inventory Management System Using C

The project aims at developing an inventory management system using the C language that enables an organization to maintain its inventory. The project inventory management system demonstrates the creation of a user interface of a system, without the use of C Graphics library. The application uses basic C functions to generate menus, show message boxes and print text on the screen. To display customized text with colors and fonts according to application requirements, functions have been created in the application, which fetch the exact video memory addresses of a target…

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Record Entry System Using C

The objective of the record entry system is to develop a login-based record keeping system, which has nested menus and different interface for different sets of users. The application record entry system contains separate interface defined for an administrator and employees. The application provides a basic menu, which has menu options for both types of users. According to the selection made by the user, the user is prompted to enter his login name and password. On successfully validation the user name and password, a menu is displayed to the user…

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