Electronic Circuits and Projects Forum

Hello Everyone

I am planning to design a scrolling display. i intend to use 74HC595 for columns and ULN2803 for driving rows.

I got a circuit from this forum which is attached along with this message. Its a circuit provided by blueroomelectronics.

I initially want to use 8, 5X7 display units and later on connect 2 such boards in series to form a 16display units in all.

I am very much confused with the overall current variations that can effect the circuit. The design aspect of it etc. I have thought of using a 100 ohm resistor instead of 150ohm as shown in the attachment.

Kindly suggest me if i am going on the right path. I dont want to blow my displays as i just have 4 of them with me right now.

Kindly suggest me a appropriate circuit or let me know if the attachment works fine.