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FND DISPLAY MICRO CONTROLLER KEYPAD COMPARATO R CIRCUIT

AA Comparator is a device that compares two voltages or currents and switches its output to indicate which is larger. AAn operational amplifier (op-amp) has a well balanced difference input and a very high gain. V out = A o (V 1 − V 2 )

The comparator output satisfies the following rules: When V + is larger than V - the output bit is 1. When V + is smaller than V - the output bit is 0

10K 100K 10K 1K 100K1K

A seven-segment display, or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot-matrix displays.display devicedecimal numeralsdot-matrix

COMMON ANODE COMMON CATHODE

Transformer + Rectifier

Smoothing

Transformer + Rectifier + Smoothing

Transformer + Rectifier + Smoothing + Regulator

A bridge rectifier makes use of four diodes in a bridge arrangement to achieve full-wave rectification

Current Flow in the Bridge Rectifier FIG(2 ) FIG(1 ) FIG(3)

FILTER SINGEL FILTER RC FILTER LC FILTER

SINGLE CAPACITOR

MICRO CONTROLLER A Microcontroller is designed for a very specific task -- to control a particular system.

A single chip that contains the processor (the CPU), non- volatile memory for the program (ROM or flash), volatile memory for input and output (RAM), a clock and an I/O control unit.

FEATURES OF PIC 16F72

A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequencyelectronic oscillatorresonance crystalpiezoelectric materialfrequency 4 MHz quartz crystalMHzquartz crystal

A photodiode consists of an active p-n junction which is operated in reverse bias. When light falls on the junction, a reverse current flows which is proportional to the illuminance. The linear response to light makes it an element in useful photodetectors for some applications p-n junction reverse bias illuminancephotodetectors

Led are used as indicator lamps in many devices and are increasingly used for other lighting.lighting

 An Opto-Coupler is a device that consists of an LED light bulb and photodiode.  An optocoupler, is "an electronic device designed to transfer electrical signals by utilizing light waves to provide coupling with electrical isolation between its input and output