# HPA L3 noiseII

 What is formula for BJT thermal noise? Vnrb= 4kTrbΔf V2 What is formula for Shot noise in BJT what terminals generate them? inb2 = 2qIbΔf A2 inc2 = 2qIbΔf A2 made by collector and base what is the knee frequency approach to the formula for flicker noise in BJT? Is it normally included/ inf2 = (2qf1IbΔf)/f A2 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 VT VT= 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 rb? Bipolar transistorsnpn have higher B0 and ft The pnps have lower rb 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 vn2 and low in2 .This is because:At low frequencies in^2 dominatesAt 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 Authorkeesukim ID339536 Card SetHPA L3 noiseII Descriptionnoise part 2 Updated2018-05-15T14:44:04Z Show Answers