transistor switching saturation calculator

rc (collector resistor) collector resistance (KΩ) 
vp (positive voltage) positive voltage (V)
Beta(min) (current gain) amplification factor, current gain
VBE (base to emitter drop)base-emitter voltage drop (V)

rb (base resistor) base resistance (KΩ) 

by load current saturation, the base current must be ib=ic/beta. transistors have different gains, so we want to use the lowest value from the beta to ensure saturation.

rb= (vp-vbe)/ib= (vp-vbe)*amplification factor/ic= (vp-vbe)*amplification factor*rc/vp