For this assignment we were given this diagram
according Motorola Datasheet current gain on BC547 transistors is 110 to 800
Voltage = 12V
choosing proper resistors for LEDs:
ILED = 30mA
VLED = 1.8V
RLED = (VSupply - VLED) / ILED
RLED = (12-1.8)/0.03= 340 Ohms
So I would use two 330R resistors for R14 and R15
β=Ic/Ib
Ib=Ic/β
Ib=30/110=0.27mA
R=(5V-0.7V)/0.00023A=18695.65 Ohms
so I choose to use 15K resistors for R13 and R16
Parts List:
BC547 transistor x 2
Green LED x 1
Red LED x 1
330R resistor x 2
15K resistor x 2
PC board
Lochmaster Diagram
Video
