What is formula for Shot noise in BJT what terminals generate them?
i_{nb}^{2} = 2qI_{b}Δf A^{2}
i_{nc}^{2} = 2qI_{b}Δf A^{2 }
made by collector and base
what is the knee frequency approach to the formula for flicker noise in BJT? Is it normally included/
i_{nf}^{2} = (2qf_{1}I_{b}Δf)/f A^{2
}Not normally included as it is negligible at higher freq compared to other noise mech
Draw the hybrid-π noise model
What is formula for V_{T}
V_{T}= kT/q
What is MOSFET formula for thermal noise
What is mosfet OG formula for Flicker noise?
What is mosfet formula for shot noise, is it normally considered in calcs?
no not really
Draw equivalent noise model of mosfet
Derive voltage and current noise equations for MOSFET noise model
forget about current noise because gate leakage current is so low.
What input device do you use when you have really low values of Rs?
Transformer coupling
What input device should you use at midrange impedances? Which should you use for high frequency applications and which should you use for lower r_{b}?
Bipolar transistors
npn have higher B_{0} and f_{t }
The pnps have lower r_{b}
What input device should you use for high values of source impedance? why?
Whats the drawback
Use mosfet for low input noise current
Drawback is that you get 10->100 times greater 1/f noise
What input device should you use for inductive sources?
A device with low vn^{2} and low in^{2} .
This is because:At low frequencies in^2 dominates
At high frequencies vn^2 dominates
What input device should you use for sources with parallel capacitance?
Vn^2 is critical so use a bipolar transistor with a high quiescent collector current to minimise this term