Display Digital

7-segment Display

A 7-segment display uses seven LED segments, plus often a decimal point, to form digits and a few letters.

Part images

7-segment display. Seven LED segments form digits. Image source: SunFounder Pico 2 W Starter Kit documentation, Components section, © 2026 SunFounder.
Common cathode symbol. SunFounder symbol for the common cathode display used in the kit. Image source: SunFounder Pico 2 W Starter Kit documentation, Components section, © 2026 SunFounder.

What it is

A 7-segment display uses seven LED segments, plus often a decimal point, to form digits and a few letters.

How students use it

Students use it for counters, timers, scores, and numeric sensor output, usually with segment codes and sometimes a 74HC595 to save GPIO pins.

Pins and power

Segments a through g plus decimal point, with common cathode pin(s).

Common cathode display in this kit. Each segment is an LED and needs current limiting.

SunFounder states this kit uses a common cathode display. Segment codes use bits for DP/G/F/E/D/C/B/A; for example 0x3f displays 0.

Voltage and safety

Every lit segment draws current. Use resistors and check total current.

Do not connect segments directly to GPIO without current limiting.

Module internals

Seven LED segments plus decimal point in one display body.

Datasheet notes

SunFounder does not identify an exact 7-segment part number. Match the display markings and common-cathode/common-anode type before applying a datasheet.

Common libraries

No special library is required; students usually map digits to segment bit patterns and write them with GPIO or a 74HC595.

Common mistakes

Using common-anode code on a common-cathode display, reversing the common pin, mixing up segment order, and forgetting the decimal point bit.