Hello Everyone,
i'm newbie in electronics.
I'm using below schematic to drive 3 digit common cathode 7 segment. udn2891 chip is expensive. so i'm using transistors array.
I want to know will the below schematic work?

 

hi Omais,
Looking thru the circuit, I have used a similar method which worked OK.
E

 

A reminder when programming is that you have to implement inter-digit blanking. You have to turn each display completely off for a small amount of time before you set the seven segments of the next display otherwise you end up with a sort of ghosting between segments.

 

hi Omais,
Looking thru the circuit, I have used a similar method which worked OK.
E

Thank you ericgibbs for your response.

 

A reminder when programming is that you have to implement inter-digit blanking. You have to turn each display completely off for a small amount of time before you set the seven segments of the next display otherwise you end up with a sort of ghosting between segments.

Thanks KeepItSimpleStupid. you are right.

 

i'm newbie in electronics.

Since you're new, let me give you some advice.

We have a strong preference for the flow in schematics to be primarily from left-to-right and top-to-bottom, with unnecessary wire jogs and scenic routing avoided. When using signal buses, it's customary to show signals entering and leaving the bus. You should also be consistent. If you use a connection dot on one 'T', you should use dots on all of them.

I want to know will the below schematic work?

If you add current limiting resistors to the bases of Q1-3, it could work. While it's unlikely that the shift register could damage the BE junctions or the shift register, it's unsightly.

To be more certain the circuit will work, you need to show all connections.

 

Example of your circuit using more typical conventions: