Audio001

                                          

25 Watt MOSFET Audio Amplifier
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Schematic design of 25W MOSFET audio amplifier
Part Components of MOSFET Audio Amplifier:
Capacitors	Resistors
C1      = 470 nF / 63V Polyester C2      = 330 pF / 63V Polystyrene C3,C5 = 470 μF / 63V Electrolytic C4,C6,C8,C11 = 100nF / 63V Polyester C7      = 100 μF / 25V Electrolytic C9      =   10pF / 63V Polystyrene C10    =    1 μF / 63V Polyester Transistors Q1-Q5 = BC560C Q6      = BD140 Q7      = BD139 Q8      = IRF532 Q9      = IRF9532	R1,R4 = 47KΩ ¼W R2      = 4K7Ω ¼W R3      = 1K5Ω ¼W R5      = 390Ω ¼W R6      = 470Ω ¼W R7      = 33KΩ ¼W R8      = 150KΩ ¼W R9      = 15KΩ ¼W R10    = 27Ω ¼W R11    = 500Ω ½W Trimmer Cermet R12,R13,R16 = 10Ω ¼W R14,R15        = 220Ω ¼W R17   = 8.2Ω 2W R18   = 0.22Ω 4W wirewound
Power supply circuit diagram
Part Components of Power Supply Circuit:
Capacitors	Resistors
C1      =     10 nF / 1000V Polyester C2,C3 = 4700 μF / 50V Electrolytic C4,C5 =   100 nF / 63V Polyester Others F1,F2 3.15A Fuses with sockets T1 220V Primary, 25 + 25V Secondary 120VA Mains transformer PL1 Male Mains plug SW1 SPST Mains switch	R1 = 3K3Ω ½W Diodes D1 200V 8A Diode bridge D2 LED (5mm. Red)
Notes
Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log potentiometer (dual gang for stereo) and a switch to cope with the various sources you need. Q6 & Q7 must have a small U-shaped heatsink. Q8 & Q9 must be mounted on heatsink. Adjust R11 to set quiescent current at 100mA (best measured with an Avo-meter in series with Q8 Drain) with no input signal. A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of R1, R4, R9, C3 to C8. Connect C11 at output ground. Then connect separately the input and output grounds at power supply ground.
Technical Data
Output power: well in excess of 25Watt RMS @ 8Ω (1KHz sinewave) Sensitivity: 200mV input for 25W output Frequency response: 30Hz to 20KHz -1dB Total harmonic distortion @ 1KHz: 0.1W 0.014% 1W 0.006% 10W 0.006% 20W 0.007% 25W 0.01% Total harmonic distortion @10KHz: 0.1W 0.024% 1W 0.016% 10W 0.02% 20W 0.045% 25W 0.07% Unconditionally stable on capacitive loads

Source : Electronics Lab