• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

SMA420564 4digit 7 segment LED display connections

Not open for further replies.
Need some info on this display. Pretty sure it's a common cathode type, and I have seen circuit diagrams showing 8 current-limiting resistors in the segment supply bus, and 4 separate driver transistors, one in each common cathode line for digit selection. My question is are these resistors and transistors contained internally in the module, or are these to be added externally? Help would be much appreciated.


Well-Known Member
Most Helpful Member
No, there won't be anything besides LEDs in the display. How you use it is up to you.

The display is multiplexed, meaning only one digit is ever on at a time. Scan through the them at over 30 Hertz and they will appear to be on continously.
Not open for further replies.

Latest threads

EE World Online Articles