Tranistor Saturation State

Transistors: base resistor selection for saturation state.

  • Need to know Maximum current load for the device to be turned on.
  • Need to know minimum HFE for transistor.
  • Divide (Maximum Current)/(Minimum HFE) to get the minimum base current
  • Add 30% to the minimum base current to be sure the transistor is saturated.
  • Use R = V/I to calculate base resistor.