Analysis of The White Emitter-Follower Amplifier

The analysis of the White emitter-follower, indicated that this circuit exhibits definite advantages over the the conventional emitter-follower in four areas: gain, input impedance, output impedance, and amplification of bipolar pulses. The feedback in the White emitter-follower accounts for he advantages.

A major disadvantage of the emitter-follower is the variation in beta, for large collector current swings, which results in unequal amplification of bipolar pulses. It has been shown that the White emitter-follower does not exhibit this non-linear beta characteristic due to the compensation of the feedback loop. A decrease in beta in the White emitter-follower will result in an increase in the driving signal, V_bel' which will tend to compensate for he beta reduction. The feedback yields an effective linear beta not possible in the emitter-follower configuration. Therefore, the White emitter-follower is able to amplify bipolar pulses with approximately equal amplitudes.