Customer:
We’re trying different approaches. Do you have a link to a tutorial on how to connect the 3-digit 7-segment display we got from you? I found various schematics but I’m not sure which one is correct - there are many different ones, and some use transistors.
Original message (Croatian)
hvala na odgovorima. Isprobavamo razne varijante.
Da li imate neki link na tutorial kako spojiti 3 digit 7 segment display
koji smo uzeli od vas. Našao sam razne sheme ali nisam siguran koja
treba, ima ih dosta različitih, i koriste tranzistore, itd.
Hvala
Originally submitted via the contact form on soldered.com on 26 April 2016. Migrated to the forum for community visibility.
Soldered Support:
These displays are common-anode, which means the anode pins (positive) for each digit are connected together, and all the cathode minuses for each segment (for example the dash in the first row) are also connected together. The datasheet is shown on our page: https://e-radionica.com/productdata/LD3361BS.pdf
You will need transistors for these common anodes, since all the current for one digit flows through these common anodes. Use regular NPN transistors on each anode - that will be sufficient. Connect each of these pins to one input/output pin, just like all these cathode pins. There are various libraries available for controlling these types of displays.
Original message (Croatian)
nadam se da ide 
Displeji su common-anode, što znači da su nožice anoda(pluseva), od svake znamenke povezane zajedno, a svi minusi za svaki segment(npr crtica u prvom redu) su također povezani zajedno. U datasheetu na našoj stranici je prikazano: https://e-radionica.com/productdata/LD3361BS.pdf
Prilažem i screenshot točno displeja kojega pitate kako biste vidjeli raspored nožica.
Trebat ćete tranzistore za ove zajedničke pluseve, budući da kroz te zajedničke pluseve prolazi sva struja jedne znamenke. Koristite obične NPN tranzistore na svakoj anodi, bit će dovoljno. Svaki taj pin spojite na jedan input/output pin, kao i sve ove pinove katoda. Imate i razne library-e za upravljanje ovakvim displejima.
Attachment omitted in migration: Screen Shot 2016-04-26 at 10.09.33.png