Class B push-pull (Transformer coupled)
In normal class B amplifier output current flows only for one half cycle i.e conduction angle is 180° to ensure 360° operation class B push-pull is used
\(Q_1\) conducts during positive half cycle of input ,so \(I_{c1}\) flows
During negative half cycle of input ,\(Q_2\) conduct \(I_{c2}\) flows.these 2 current are combined at output
Eficiency
\( V_{pp}=2V_{cc}\)
\( I_{pp}=\frac{2V_{cc}}{R^{,}_{L}}\)
This circuit resembles action of a fullwave rectifier therfore
\( I_c=\frac{2I_{m}}{Π}=\frac{2V_{cc}}{ΠR^{,}_{L}}\)
\(η =\frac{V_{pp}I_{pp}}{8V_{cc}I_c}\)
\(=\frac{2V_{cc}\frac{2V_{cc}}{R^{,}_{L}}}{8V_{cc}\frac{2V_{cc}}{ΠR^{,}_{L}}}=\frac{Π}{4}\)=78.5%MathJax example
In normal class B amplifier output current flows only for one half cycle i.e conduction angle is 180° to ensure 360° operation class B push-pull is used
\(Q_1\) conducts during positive half cycle of input ,so \(I_{c1}\) flows
During negative half cycle of input ,\(Q_2\) conduct \(I_{c2}\) flows.these 2 current are combined at output
Eficiency
\( V_{pp}=2V_{cc}\)
\( I_{pp}=\frac{2V_{cc}}{R^{,}_{L}}\)
This circuit resembles action of a fullwave rectifier therfore
\( I_c=\frac{2I_{m}}{Π}=\frac{2V_{cc}}{ΠR^{,}_{L}}\)
\(η =\frac{V_{pp}I_{pp}}{8V_{cc}I_c}\)
\(=\frac{2V_{cc}\frac{2V_{cc}}{R^{,}_{L}}}{8V_{cc}\frac{2V_{cc}}{ΠR^{,}_{L}}}=\frac{Π}{4}\)=78.5%
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