Presentation onOver-/under-voltage

protection of electrical appliance

Submitted by:rakesh roshan(0701209329)

nishant kumar(0701209350)abhishek pattnaik(0701209404)

narayan singh(0701209288) ashish kumar nayak(0701209345)

Under guidance of Er. Alice Pradhan

Introduction: Sudden fluctuation in supply is a very big problem in

industries and domestic applications. It causes a

major loss for industries, offices and homes.

This project gives a low cost and powerful solution for

this problem. This Circuit protects refrigerators ,ACs,

Microwave ovens as well as other appliances from

over and under voltage fluctuations.

Block diagram:

Circuit diagram

Simulated circuit diagram

Components:

TRANSFORMER

IC 7812

LM 324 (OPERATIONAL AMPLIFIER)

RELAY

ZENER DIODE

npn TRANSISTOR

RESISTORS ,CAPACITORS AND DIODES

TRANSFORMER

Step down transformer 230V/12V

Operating frequency is 50HZ.

Voltage is converted from 230v to 12v.

Current rating is 1A.

IC LM7812 (VOLTAGE REGULATOR)

Output current in excess of 1A.

Output Voltages of 12V.

current Internal thermal overload protection.

No external components required.

Output transistor safe area protection.

Internal short circuit limit.

IC LM324(OPERATIONAL AMPLIFIER)

Features :

Large DC voltage gain:100 dB

Wide power supply range:

Single supply:3VDC to 32 VDC

Dual supplies:±1.5VDC to ±16VDC

Differential input voltage range equal to the power supply voltage

Power drain suitable for battery operation

Large output voltage swing:0VDC to VCC-1.5VDC

PIN CONFIGURATION (LM 324)

Its rating is 12v, 200 ohm ,1 c/o relay.

Relay

•SPDT – Single Pole Double Throw.

A common terminal connects to either of two others.

Including two for the coil, such a relay has five terminals in

total.

A relay is an electrically operated switch.

A Zener diode is a type of diode that permits current not only

in the forward direction like a normal diode, but also in the

reverse direction if the voltage is larger than the breakdown

voltage known as "Zener knee voltage" or "Zener voltage“.

Zener diode of rating 6.0 v and 6.8 v are used in the circuit.

ZENER DIODE

BC 547 transistor is used in the circuit.

Transistor is used to energise the relay

when op-amp goes high.

npn TRANSISTOR

Diodes

Resistor

capacitor

RESISTORS ,CAPACITORS AND DIODES

APPLICATIONS: Industrial machinery

House hold items like TV, refrigerator, AC

Agriculture Motors

Water pumps

ADVANTAGES: Highly sensitive

Fit and Forget system

Low cost and reliable circuit

Complete elimination of manpower

Can handle heavy loads up to 7A

Auto switch OFF in abnormal conditions

Auto switch ON in safe conditions

CONCLUSION:It is helpful in protecting electrical appliances in very

effective way.

REFERENCE:

1) www.wikipedia.org

2) www.efy.com

3) www.google.com

THANKs..