# BJT Voltage Divider

Thread Starter

#### creaver31

Joined Feb 2, 2012
65
Hi,
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.

#### PaulEE

Joined Dec 23, 2011
474
Hi,
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.
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