This project is extremely helpful for any fridge. The timing of the inbuilt defroasting facility is very low. As such it is necessary to defroast the accumulated ICE manually. With the help of this project, the timing can be extended upto 24 hrs. and the efficiency of the fridge can be enhanced.
TECHNICAL DESCRIPTION AND WORKING
This project has been developed and tested O.K. in our TV Engineers Technical Lab. The components and PCB used in the projects published in our books are available for sale at resonable price.
Each and every fridge manufactured in INDIA does not incorporate the inbuilt defroasting facility. This problem is over come through this project. This can be also used with the deep-freezer of your shops. The working of the project depends on the Dual four bit Binary Counter IC 74LS393. The IC555 works as a monostable multivibrator in the project and generates a decided clock pulses. When the input pin no. 1 of the IC 74LS393 receives 16 pulses, its output generates only one pulse. The second outputs operates second 16 pulses. As the last outputs do not operate 256 x 256 pulses are required for the operation of the first output for second time. This project works on this principle and the relay becomes ON/OFF either manually or automatically through the transistors SL100 and BC148. It timing can be adjusted through the preset while the function can be adjusted through Auto/Manual switch.
PRECAUTIONS WHILE ASSEMBLING THE PROJECT:-
*Check polarity of electrolytic capacitor while mounting on PCB otherwise reverse connection may damage it.
*Check polarity of diodes [anode and cathode]
*Check short circuit , while SOLDERING.
*Please use resistance of the exact value as given in the circuit.
*While mounting transistor, you should connect collector , base & emitter properly.
*First of all check all the components as per circuit.
*Use IC base for mounting of the ICs otherwise IC may damage due to current leakage of soldering iron.
IC 74LS393 = 1
IC 555 = 1
RELAY 12V = 1
TRANSISTOR SL100 = 1
BC 148 = 1
22MFD/25V = 1
100MFD/25V = 1
.1 = 1
DIODE IN4007 = 1
5.1V ZEENER = 1
150E = 1
10K = 3
1K = 1
470K = 1
150K = 1
PRESET 1M = 1
ONE POLE TWO WAY SWITCH = 1