deniah
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I build clock with 6 common cathode seven segment displays. Display drivers are 6 shift registers 74HC595 and 6 x 6 NPN BC337. From PIC I use two ports to drive 4 leds for time separator and two leds for date separator, all via BC337.
BC337 collector is connected to +12V, emitters connected to 280R and then to one segment, or time-date separator led.
Positive logic is used in software.
Problem is that separator leds are working ok, but displays are not. Logic levels on HC595 are ok, but there is no output on BC337.
Can someone help me with this?
Here is schematic.
BC337 collector is connected to +12V, emitters connected to 280R and then to one segment, or time-date separator led.
Positive logic is used in software.
Problem is that separator leds are working ok, but displays are not. Logic levels on HC595 are ok, but there is no output on BC337.
Can someone help me with this?
Here is schematic.