What is a multiplexed seven-segment display and how does it work?
1 Answer
A multiplexed seven-segment display is a type of electronic display commonly used to show numerical digits or some basic characters. It consists of seven individual LED segments arranged in a specific pattern to display numbers and a few additional characters. The segments are labeled with letters A through G, and they can be turned on or off to create various numerical and alphabetic characters.
The seven-segment display is often used to display digits (0-9) and sometimes additional characters like A, B, C, D, E, F for hexadecimal displays. To display different numbers or characters, you need to turn on specific combinations of the individual segments.
A typical seven-segment display looks like this:
mathematica
Copy code
A
F B
G
E C
D
Here's how the segments are generally used to represent each digit:
lua
Copy code
A
-----
F| |B
| G |
-----
E| |C
| |
-----
D
To display a specific digit on a single seven-segment display, you would turn on or off the appropriate segments. For example, to display the digit "0," you would turn on segments A, B, C, D, E, and F while keeping segment G off.
Multiplexing comes into play when you want to display multiple digits using a single set of seven-segment displays. Instead of having separate displays for each digit, multiplexing allows you to cycle through the digits rapidly, creating the illusion that they are all displayed simultaneously.
Here's how multiplexing works:
Digit Selection: Let's say you have four digits to display (e.g., a digital clock). You'd use four seven-segment displays, one for each digit. However, you'd only turn on the segments for one digit at a time.
Rapid Switching: You quickly switch between the displays and turn on the segments for the current digit you want to display. This switching happens so fast that the human eye perceives all the digits as being lit simultaneously.
Persistence of Vision: Due to the phenomenon known as persistence of vision, the displayed digits appear to be continuous even though each digit is only on for a fraction of a second. This is the same principle that makes motion pictures and TV work.
By multiplexing the display, you can achieve the appearance of multiple digits being displayed concurrently, while in reality, only one digit is actively lit at any given moment. This technique saves power and reduces the number of required pins or connections on the microcontroller or driver, making it efficient for displaying numerical information in various applications like digital clocks, calculators, digital counters, and more.
The seven-segment display is often used to display digits (0-9) and sometimes additional characters like A, B, C, D, E, F for hexadecimal displays. To display different numbers or characters, you need to turn on specific combinations of the individual segments.
A typical seven-segment display looks like this:
mathematica
Copy code
A
F B
G
E C
D
Here's how the segments are generally used to represent each digit:
lua
Copy code
A
-----
F| |B
| G |
-----
E| |C
| |
-----
D
To display a specific digit on a single seven-segment display, you would turn on or off the appropriate segments. For example, to display the digit "0," you would turn on segments A, B, C, D, E, and F while keeping segment G off.
Multiplexing comes into play when you want to display multiple digits using a single set of seven-segment displays. Instead of having separate displays for each digit, multiplexing allows you to cycle through the digits rapidly, creating the illusion that they are all displayed simultaneously.
Here's how multiplexing works:
Digit Selection: Let's say you have four digits to display (e.g., a digital clock). You'd use four seven-segment displays, one for each digit. However, you'd only turn on the segments for one digit at a time.
Rapid Switching: You quickly switch between the displays and turn on the segments for the current digit you want to display. This switching happens so fast that the human eye perceives all the digits as being lit simultaneously.
Persistence of Vision: Due to the phenomenon known as persistence of vision, the displayed digits appear to be continuous even though each digit is only on for a fraction of a second. This is the same principle that makes motion pictures and TV work.
By multiplexing the display, you can achieve the appearance of multiple digits being displayed concurrently, while in reality, only one digit is actively lit at any given moment. This technique saves power and reduces the number of required pins or connections on the microcontroller or driver, making it efficient for displaying numerical information in various applications like digital clocks, calculators, digital counters, and more.