The 74HC75 is a versatile digital logic component that functions as a quad 2-input multiplexer/demultiplexer. It is designed to select between two data inputs and route them to any of its four outputs. This component is widely used in digital circuits for data routing, signal selection, and various control applications where multiple data sources need to be managed efficiently.
This circuit uses a 74HC595 shift register to control multiple LEDs via a common ground configuration, with a microcontroller providing serial data input. It includes decoupling capacitors for stability and a 12-Bit DAC, potentially for analog signal generation or reference voltage application.
Open Project in Cirkit Designer
This circuit uses a Teensy 4.0 microcontroller to control a MAX7219 LED driver, which in turn drives three 7-segment displays. The microcontroller runs code to display numbers from 0 to 999 on the 7-segment displays, with the SN74AHCT125N buffer providing signal integrity and the necessary capacitors and resistors ensuring stable operation.
Open Project in Cirkit Designer
This circuit is a simple flip-flop based LED control system. It uses a 74HC74 D flip-flop to toggle the state of an LED, with push switches to control the clock and data inputs. The circuit also includes a 7408 AND gate and a BC547 transistor to drive the LED.
Open Project in Cirkit Designer
This circuit is a microcontroller-based LED control system using an Arduino UNO and multiple 74HC595 shift registers to drive various colored LEDs. The circuit also includes touch sensors for user input and transistors for switching, allowing for complex lighting patterns and user interaction.
Open Project in Cirkit Designer| Pin Number | Name | Description |
|---|---|---|
| 1 | S0 | Select input for multiplexer/demultiplexer |
| 2 | Z0 | Output/Input 0 |
| 3 | Z1 | Output/Input 1 |
| 4 | GND | Ground (0V) |
| 5 | Z2 | Output/Input 2 |
| 6 | Z3 | Output/Input 3 |
| 7 | E | Enable input (active LOW) |
| 8 | Vcc | Positive supply voltage |
| 9 | Y1 | Data input/output 1 |
| 10 | Y0 | Data input/output 0 |
| 11 | S1 | Select input for multiplexer/demultiplexer |
| 12-15 | Z4-Z7 | Output/Input 4-7 (for additional multiplexer sections) |
Q: Can the 74HC75 be used with an Arduino? A: Yes, the 74HC75 can be interfaced with an Arduino, provided that the logic levels are compatible.
Q: What happens if the enable pin is left floating? A: If the enable pin is left floating, the outputs may enter a high-impedance state, leading to unpredictable behavior.
Q: Can the 74HC75 be used as a demultiplexer? A: Yes, by using the outputs (Z0 to Z7) as select lines and the inputs (Y0 and Y1) as common data lines, the 74HC75 can function as a demultiplexer.
Below is an example of how to control the 74HC75 with an Arduino UNO:
// Define the Arduino pin numbers for the 74HC75 control pins
const int enablePin = 2; // Connect to the E pin of 74HC75
const int selectPin0 = 3; // Connect to the S0 pin of 74HC75
const int selectPin1 = 4; // Connect to the S1 pin of 74HC75
void setup() {
// Set the control pins as outputs
pinMode(enablePin, OUTPUT);
pinMode(selectPin0, OUTPUT);
pinMode(selectPin1, OUTPUT);
// Disable the 74HC75 by setting the enable pin HIGH
digitalWrite(enablePin, HIGH);
}
void loop() {
// Enable the 74HC75 by setting the enable pin LOW
digitalWrite(enablePin, LOW);
// Select input Y0 by setting S0 and S1 to LOW
digitalWrite(selectPin0, LOW);
digitalWrite(selectPin1, LOW);
// Add a delay to observe the output
delay(1000);
// Select input Y1 by setting S0 LOW and S1 HIGH
digitalWrite(selectPin0, LOW);
digitalWrite(selectPin1, HIGH);
// Add a delay to observe the output
delay(1000);
// Add additional logic here to control the multiplexer as needed
// Disable the 74HC75 before ending the loop
digitalWrite(enablePin, HIGH);
// Add a delay to observe the disabled state
delay(1000);
}
This code snippet demonstrates the basic control of the 74HC75 using an Arduino UNO. It toggles between the two inputs Y0 and Y1 and enables/disables the device. Remember to connect the 74HC75 pins to the corresponding Arduino pins as defined in the code.