Q about Smallbear darlington article

[fuzzy645]

My question is regarding this most interesting article by Smallbear on Darlington's

https://www.smallbearelec.com/HowTos/GeDarlingtons/GeDarlingtonPairs.htm



I have 2 questions regarding the use of a pair of bias resistors to turn Q2 "off" enough to bring the composite gain and leakage.

• Suppose we know both the gain and the leakage of Q1 and Q2.  If so, I am just wondering if there is a mathematical formula one can use to choose the values of R1 and R2.  To use an example with real #'s, lets say Q1 has a gain of 20 and leakage of 10, while Q2 has a gain of 40 and a leakage of 15.  Given those parameters, how can we use math to figure out the values of R1 and R2.
  


• The way R1 and R2 are configured between the 2 tranny's, would it be functioning as some kind of voltage divider?

Thanks!

[PRR]

That's just an example test jig.

You should be looking at the functional circuit.