Current Sink / concepts:
1. If a positive current to the circuit to provide a certain point, that is pulled;
2. If the circuit provides a negative current to a certain point, for the filling;
NPN transistor that is a sinking current;
PNP transistor collector to a vertical load, referred to as a pull-up current;
But they are current source.
Single endfire collector follower power estimation process
The power of the speaker is 10W, 8Ω,
Power P = U * U / R, so that U * U = 80; take ± 9V voltage meet the requirements.
Required voltage VE to reach ± 9V.
Features:
1. whether or not the input signal, which constant-current output circuit flows;
2. The advantages of the distortion, the smaller the signal, the higher the fidelity.
Disadvantages:
1. Power efficiency is too low, when the input signal does not reduce power consumption. About 25% power efficiency.
Because of its high fidelity, some senior audio equipment with a Class A amplifier.
In order to improve the power efficiency, there has been a push-pull emitter follower
In the positive half cycle Q1 is turned on, Q2 is turned on during the negative half cycle,
For zero input when there is no collector current and loss. The output power of 10W, 10W loss of each tube below.