Electronics Handbook/Devices/Amplifier/DC Volatge Amplifier

${\displaystyle {\frac {V_{s}}{V_{p}}}={\frac {N_{s}}{N_{p}}}}$

Transformer acts as Amplifier if N₂ > N₂

When Transistor conducts current

I_b ≠ 0 , I_e = α I_b , I_c = β I_b

${\displaystyle {\frac {V_{o}}{V_{i}}}=1-{\frac {R_{2}}{R_{2}+R_{1}}}{\frac {R_{3}}{R_{4}}}}$

When R₁

${\displaystyle {\frac {V_{o}}{V_{i}}}=1-{\frac {R_{3}}{R_{4}}}}$

${\displaystyle {\frac {V_{o}}{V_{i}}}=-n}$ provided that R₃ = (n+1)R₄

${\displaystyle {\frac {V_{o}}{V_{i}}}={\frac {R_{2}}{R_{2}+R_{1}}}{\frac {R_{3}}{R_{4}}}}$

When R₁

${\displaystyle {\frac {V_{o}}{V_{i}}}={\frac {R_{3}}{R_{4}}}}$

${\displaystyle {\frac {V_{o}}{V_{i}}}=n}$ provided that R₃ = nR₄

${\displaystyle V_{\mathrm {out} }=-V_{\mathrm {in} }\left({R_{f} \over R_{1}}\right)}$

${\displaystyle V_{\mathrm {out} }=V_{\mathrm {in} }\left(1+{R_{2} \over R_{1}}\right)}$