2B-BI-COLOURED L.E.D BLINKER
You can use this gadget to decorate your home . The project employes Bi- coloured L.E.Ds. As such the OFF/ON of the colours appear more attractive and enhances the beauty of display boards.
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.
This project is mainly based on IC 7400. Bi-coloured L.E.Ds are employed in the project which emits different colour light on forward and reverse bias. The IC 7400 has 4 NAND gates. The IC is a TTL circuit and two NAND gates of the IC are utilized here in the from of multibirator . The IC gates are first- pin no. 1, 2 ,3 2nd- 4, 5, 6 3rd – 12, 13, 11 and 4th 10, 9, 8 . Both the outputs of the IC are connected to each other. When one output is high, the other remains low. This high/low information is obtained from pin no 6 through the multivibratior. The Bi-coloured L.E.Ds connected in parallel with the 4th and final gate receive contineous forward, reverse bias and as a result we perceive blinking of two different colours.
PRECAUTIONS WHILE ASSEMBLING THE PROJECT:-
*Check +ve & -ve terminal of L.E.D. while mounting on PCB.
*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.
*Check polarity of electrolytic capacitor while mounting on PCB otherwise reverse connection may damage it.
*Clean PCB after SOLDERING, so that the component or print do not short.
IC 7400 = 1
BI-COLOURED L.E.D. = 6
10K = 2
10MFD/25V = 2