ve3sjk
Newbie level 3
I am trying to control a custom 7 segment display using the circuit below using the 18F452 chip.
RA0 seems to have no effect i get 12 volts regardlesss of a one or zero on its output. If i ground the base manually it works perfectly just not working via the PIC. The RA0 is changing as desired.
What are the proper transistors to use for both the 12v switching (digit select) and if i wanted to replace the 2803a with descrete transistors. Since I am going to need to order the parts i need i would like to order the proper transistors and resistors the first time.
Each segment draws 25 mA and the total per digit would be 175 mA while diplay the number 8..
Here is what i have now
RA0 seems to have no effect i get 12 volts regardlesss of a one or zero on its output. If i ground the base manually it works perfectly just not working via the PIC. The RA0 is changing as desired.
What are the proper transistors to use for both the 12v switching (digit select) and if i wanted to replace the 2803a with descrete transistors. Since I am going to need to order the parts i need i would like to order the proper transistors and resistors the first time.
Each segment draws 25 mA and the total per digit would be 175 mA while diplay the number 8..
Here is what i have now
