Hi everyone, in this article we are going to learn about how to build an electronic circuit that is able to count up and down displayed on a seven segment display. This kind of circuit is generally known as a counter up counter down or count up count down.
Where do we need this counter up and counter down actually?
Absolutely, this kind of circuit is very common used in our daily life. It just we didn’t realize that this circuit is everywhere around us and we often see it. Most often we see this is on the display of a gas pump which implements the counter up system that will count up based on the amount of fuel or gas coming out of the hose pump into your fuel tank.
Another example is a score board. Yup, every score made by a player will increase his/her point, and then the point from the score board will also be added. This score board also uses the counter up for adding the point while the counter down for cutting down the point or even fixing it if an error occurs while adding the point. There are so many examples around us.
Some interesting articles to be read:
Alright, now let’s begin creating a simple electronic circuit that able to display numbers on seven segment display led, the total number displayed can be increase or decrease according to us with a button for help.
For this project we need some main components such as:
- IC 74192 (IC Synchronous 4-Bit Up/Down Counters)
- IC 7447 or 74247 (BCD to 7-Segment Decoder/Driver)
- Seven segment display with common anoda
- Resistor 10k
The core project is an IC 74192 that plays important role from the whole circuit available. IC 74192 is a counter up IC and also can be used as counter down. The output is BCD data (Binary Coded Decimal) which has 4 outputs represent the binary numbers.
If the input clock of this IC counter is given a clock cycle (high and low) then its BCD output value will change depend on where the clock is given, on the clock up or the clock down?
The pin of the input clock lies on the 4th and 5th pin of the IC. The \4th pin is the input clock for counting down while the 5th one is for counting up.
This kind of output that result as BCD data is very difficult to understand for common people because they have to translate the binary numbers to decimal one firstly. Therefore we use an IC which capable on solving the conversion problem directly. This IC is 7447 or 74247.
7447 or 74 247 IC is an IC that is capable for converting binary to decimal data with the help of seven segment display. So, does this IC have decimal data output? The answer is no. 7447 or 74247 IC has an output in the form of the pin configuration of the segment on seven segment display, which is from “a” segment to “g” segment. The alteration this IC output is depends on binary value of the input. For example, the input is 0001 and its decimal value is 1, so the output of the IC will give a low signal to the “b” and “c” segments and give high signal to the other segments. Because the segment used has a type of common anode (….) so it means that each segments will active if get the low signal from IC 7447 / 74247. And because the “b” and “c” segments are given low signal then the number that will appear on the seven segment display will be number “1”.
After understanding the operation of each IC then simply arrange the circuit as shown on the picture, you can adjust the input current to the seven segment display using a resistor in each segment or using additional driver if you want to make a bigger seven segment.
You can see from the circuit, the input clock which are UP and DN, I connect them using a button and resistor. The button used for giving the high or positive signal to the input clock, but when the button is released then the resistor will connect the low or negative signal to the input clock because the positive source has been disconnected. A single clock cycle given that the high and the low will change the resulting value of the number, it can be increased or decreased according to where the clock is given.
For the proteus simulation file of this project, you can download it freely through the link given bellow. You can modify it according to your needs. For the counter up and counter down circuit with many output of seven segment, I will discuss it in my next article.
DOWNLOAD FILE SIMULASI[/sociallocker]