MAINS SUPPLY SENSED Over Voltage Submitted By

Introduction The aim of the project is to make a low voltage and high voltage indicator. This system will save costly electrical and electronic appliances from the adverse effects of very high and very low mains voltages. The circuit features auto reset and utilizes easily available components. It makes use of the comparators available inside 555 timer ICs. Supply is tapped from different points of the power supply circuit for the display and control circuit operation to achieve reliability.

2.BLOCK DIAGRAM REFER CD

TRANSFORMER Transformers convert AC electricity from one voltage to another with a little loss of power. Step-up transformers increase voltage, step-down transformers reduce voltage. The input coil is called the primary and the output coil is called the secondary. There is no electrical connection between the two coils; instead they are linked by an alternating magnetic field created in the soft-iron core of the transformer.

LM339( COMPARATOR) The LM339 consists of four independent precision voltage comparators The LM339 series was designed to directly interface with TTL and CMOS. When operated from both plus and minus power supplies, the LM339 series will directly interface with MOS logic where their low power drain is a distinct advantage over standard comparators.

FEATURES Wide single supply voltage range 2.0VDC TO 36VDC or dural supplies ±1.0VDC to ±18VDC ● Very low supply current drain (0.8㎃) independent of supply voltage (1.0㎽/comparator at 5.0VDC) ● Low input biasing current 25㎁ ● Low input offset current ±5㎁ and offset voltage ● Input common-mode voltage range includes ground ● Differential input voltage range equal to the power supply voltage ● Low output 250㎷ at 4㎃ saturation voltage ● Output voltage compatible with TTL, DTL, ECL, MOS and CMOS logic system ● Moisture Sensitivity Level 3

1N4007 Diodes are used to convert AC into DC these are used as half wave rectifier or full wave rectifier. Three points must he kept in mind while using any type of diode.

ZENER DIODE

The resistor, RS is connected in series with the zener diode to limit the current flow through the diode with the voltage source, VS being connected across the combination. The stabilised output voltage Vout is taken from across the zener diode. The zener diode is connected with its cathode terminal connected to the positive rail of the DC supply so it is reverse biased and will be operating in its breakdown condition.

BC547 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  

RELAY IT IS A ELECTRO MAGNETIC SWITCH USED TO CONTROL THE ELECTRICAL DEVICES COPPER CORE MAGNETIC FLUX PLAYS MAIN ROLE HERE

Relay Driver ULN2003 ULN is Relay driver application The ULN2003 is a monolithic high voltage and high current Darlington transistor arrays. It consists of seven NPN Darlington pairs that features high-voltage outputs with common-cathode clamp diode for switching inductive loads. The collector-current rating of a single Darlington pair is 500mA. The Darlington pairs may be paralleled for higher current capability.

Contd … The ULN functions as an inverter. If the logic at input 1B is high then the output at its corresponding pin 1C will be low.

LOAD INDUCTIVE LOAD: An inductive load consists of a load created by a wire wound coil, such as in a relay or solenoid, a transformer, or any load which uses a winding over a magnetic iron core. Breaking an inductive load is usually more severe than breaking a resistive load and will generally produce heavy arcing.

Applications This project is applicable for Solar Power Plant where voltage parameters should match with the Power grid.

Advantages

DISADVANTAGE

BIBILOGRAPHY Wikipedia.in www.beyondlogic.org www.wikipedia.org www.howstuffworks.com www.alldatasheets.com

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