| 摘要 |
PURPOSE: A low dissipation and high efficiency output type audio amplifier is provided to improve the output efficiency of an amplifier itself by steadily activating power amplifier devices. CONSTITUTION: A voltage amplifier(1) amplifies voltage about a minute acoustic signal which is inputted. A output terminal power amplifier(2) amplifies an acoustic signal which is outputted through the voltage amplifier. The amplified acoustic signal is outputted to a speaker(SP). A power voltage supplier(3) supplies voltage for driving each part of an amplifier. A zener diode(ZD1) for power amplifier output voltage detect is connected among resistance for protection(R1), an output port of the power amplifier, and a high voltage output port of the power voltage supplier. A transistor(TR1) for by-pass voltage variableness varies the base bias voltage of a load amount adjustment transistor. |
