DS

CLASS B PUSH PULL AMPLIFIER The circuitry for the Class B Push-Pull amplifier operation is the same as that for the Class A operation except that the device are biased at cutoff. ADVANTAGES OF CLASS B PUSH PULL AMPLIFIER OVER CLASS A It is possible to obtain greater power output. Class B power amplifier provides practically 4 times the power supplied by a single ended amplifier provided load resistance remains the same It gives higher operating efficiency (theoretically 78.5%). It is primarily due to the fact that no power is drawn by the circuit under Zero signal condition. Because of above advantages, a push-pull class B transistor circuit is preferred in systems Where the power supply is limited, such as those operating from solar cells or battery. The automatic cancellation of all even order harmonics from the output makes class B push-pull amplifiers highly desirable communication sound equipment. DRAWBACKS OF CLASS B PUSH-PULL AMPLIFIER The Harmonic distortion is Higher. Self ...

MAIN DIGITAL BOARD SCHEMATIC                                        Service Mode - SMPS circuit diagram - and more =>

18W Class-B Audio Amplifier with Tone Controls 18W Class-B Audio Amplifier with Tone Controls In order to satisfy repeated requests by correspondents, a medium power audio amplifier incorporating tone controls in the feedback path was finally designed. To avoid an excessive increase in parts-count, due to the addition of the tone controls, a simple amplifier circuitry was designed on the same guidelines of the successful 45 Watt Class B Amplifier, but using the excellent NE5534 IC instead of a discrete component op-amp to drive the output "dumper" transistors. The particular circuit configuration, allowed to push the NE5534 exceptional capacity of driving the output transistors near to its limits, enabling the whole amplifier to deliver relatively high power outputs without problems. For this reason, it was possible to obtain 18W into an 8 Ohm load using a power supply voltage of +/- 20V. Despite the complication added by the tone controls, the amplifier has an input sensitiv...