BJT Voltage Divider

Discussion in 'General Electronics Chat' started by creaver31, Feb 9, 2012.

  1. creaver31

    Thread Starter Member

    Feb 2, 2012
    I need to make a program using voltage divider bias of BJT. The given inputs are Vcc, Beta, Ic, Vce and Rc. I know how to find Rb(Rth) by the formula
    "Rth = 0.1*Beta*(Vcc/Ic) - 1.5*Rc"

    but the problem is i don't know how can i find the values of R1 and R2.
    I just need the equation.

    Thanks in advance.
  2. PaulEE


    Dec 23, 2011
    Voltage out of the divider is Vout = Vin (R2/(R1+R2)), where R2 is the bottom resistor from which the voltage appears.

    The second equation will involve a voltage loop including R2, V- (or ground), the base-emitter diode, and the emitter resistor, if there is one.

    Did that help?

    Gotta solve two equations for two unknowns