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In this project, I will make a circle-led counter circuit.

Front Side

List of Materials

-1 Piece NE555 Timer
-1 Piece 74HC154 Demultiplexer
-1 Piece 74LS93 Counter
-2 Pieces 74LS90 Counter
-2 Pieces 74LS47 BCD Decoder
-14 Pieces 100R Resistors
-1 Piece 1K Resistor
-1 Piece 2K2 Resistor
-1 Piece 10K Trimpot
-16 Pieces 5mm LEDs
-2 Pieces 38mm 7 Segment Displays
-1 Piece 4u7 16V Capacitor
-1 Piece 100nF Capacitor
-1 Piece 10x10cm PCB Board

Preparation for the Circuit

Our circuit consists of 5 parts. These are the clock circuit, the main counter circuit, LED driver and shift register circuit, 7 Segment Display driver circuit, and Counter circuit for displays.

In the middle of our circuit, 2, 7 Segment Displays and There will be 16 LEDs arranged in a circle around it.

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I assembled the circuit on the prototype PCB board. It should not be exposed to heat for a long time when soldering integrated circuits.

I built the clock circuit using NE555. On other topics, I explained in detail how it works.

As you can see in the circuit diagram, I connected the cathode of 16 LEDs to the output port of the 74HC154 and connected the anodes of the LEDs with the current limiting resistor.
I connected the BCD output of the 7493 to the BCD input port of the 74154.
Thus, when I apply a clock pulse to Input A, it starts counting in BCD format.

How it Works

As with the 74LS93, I connected the QA output of the 74LS90 to Input B. When clock pulse is applied to Input A, it starts counting from 0-9 and 7 segments with 7447 are displayed on the display.

When the 15th output of the 74HC154, which drives the LEDs arranged in a circle, is active, 1 pulse occurs at the clock input of the 7490 counter and the count value increases by 1.

In this way, when the circle completes 1 turn, the value on the screen increases by 1.

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