The 0.36-inch 4-digit 7-segment Red LED Display is a compact numeric display designed for counters, timers, measurement instruments, power supplies, electronic scoreboards, and microcontroller-based projects.

It features four red LED digits with 0.36-inch-high characters, individual decimal points, and a common cathode (CC) configuration. The display uses a standard 12-pin package and is designed for multiplexed operation, making it suitable for use with Arduino, ESP32, Raspberry Pi Pico, and other microcontrollers.

Key Features

• Display Type: 7-segment LED
• Number of Digits: 4
• Digit Height: 0.36 inch
• LED Color: Red
• Configuration: Common Cathode (CC)
• Decimal Point: Yes
• Package: 12-pin
• Continuous LED Current: Up to 20 mA
• Peak Pulsed Current: Up to 100 mA
• Compact and easy to integrate into PCB designs
• Bright, easy-to-read numeric characters
• Designed for multiplexed operation
• Suitable for microcontroller-based applications

How It Works

Each digit contains seven individual LED segments, labeled A through G, plus an additional LED for the decimal point (DP).

Because this is a common cathode display, the cathodes of the LED segments belonging to each digit share a common connection. These digit-select connections are typically identified as D1, D2, D3, and D4.

To illuminate a particular segment, the corresponding segment's anode is driven HIGH while the required digit's common cathode is activated.

Multiplexed Operation

The segment connections (A–G and DP) are shared between all four digits. Therefore, the display is normally operated using multiplexing.

During multiplexing, the controller rapidly activates D1 through D4 one at a time while applying the required segment pattern for each digit. This process happens fast enough that all four digits appear continuously illuminated to the human eye.

This technique reduces the number of microcontroller pins required to control the complete display.

Current-Limiting Resistors

Current-limiting resistors should be used with the LED segment connections to protect both the display and the controlling microcontroller.

Using an individual resistor for each segment line is recommended because it provides more consistent brightness regardless of how many segments are illuminated.

Typical Applications

• Digital voltmeters
• Digital ammeters
• Variable power supply displays
• Electronic counters
• Digital timers
• Clocks
• Frequency displays
• Electronic scoreboards
• Reaction timers
• Measurement instruments
• DIY electronics projects
• Arduino and ESP32 projects
• Flight simulator control panels
• Embedded control systems