Power-Amp-MOSFET | Electronic Project Circuits

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Amplifier MOSFET HIFI 240W by BUZ23

Here is Circuit Power Amplifier MOSFET HIFI 240W by BUZ23

Source: http://electronics-diy.com/electronic_schematic.php?id=581

Be the first to comment - What do you think? Posted by admin - January 24, 2008 at 9:54 am

Categories: mosfet amp Tags: ocl amp, Power-Amp-MOSFET

Simple Audio Power Amplifier 60W by K1058, J162

mosfet amplifiers there is no clear distinction between class-B and class-AB. For a bipolar output stage it is common to call a design class-B if the quiescent current, Iq, is adjusted for minimum crossover distortion, and class-AB if the current is increased well above this optimum level so that operation remains in class-A for small signals. (Not everyone agrees on this convention but it seems a sensible choice, for audio amplifiers at least, because these two classifications have rather different design problems. For example ‘class-B’ usually requires far more accurate quiescent current setting and thermal compensation for best results.) Class-AB causes higher distortion than class-B at higher signal levels where device switching starts to occur. For mosfets the distortion is generally highest at low quiescent current and reduces as Iq is increased, so there is not a similar optimum value giving minimum distortion. My choice of 100mA for the circuit presented here is because the mosfets used have zero temperature coefficient around this value, but with adequate heatsinks the current could be increased. With reduced supply voltage the circuit can even be biased into class-A for the lowest distortion, and here mosfets have some advantage because of their nearly square-law characteristics. If they were perfectly square-law then the peak output current in class-A would be 4 x Iq instead of 2 x Iq for typical bipolar output stages, and up to this level the distortion would be zero for ideal accurately matched complementary devices. Unfortunately well matched pairs are unobtainable, and they are not very accurately square-law, and they have non-linear capacitances, so even class-A still has its problems.

Mini-MosFet Audio Amplifier 30W by IRF530-IRF9530

This project was a sort of challenge: designing an audio amplifier capable of delivering a decent output power with a minimum parts count, without sacrificing quality.
The Power Amplifier section employs only three transistors and a handful of resistors and capacitors in a shunt feedback configuration but can deliver more than 18W into 8 Ohm with <0.08% THD @ 1KHz at the onset of clipping (0.04% @ 1W – 1KHz and 0.02% @ 1W – 10KHz) and up to 30W into a 4 Ohm load.
To obtain such a performance and to ensure overall stability of this very simple circuitry, a suitable regulated dc power supply is mandatory. This is not a snag because it also helps in keeping noise and hum of the preamp to very low levels and guarantees a predictable output power into different load impedances. Finally, as the amplifier requires only a single rail supply, a very good dc voltage regulator capable of supplying more than 2 Amps @ 40V can be implemented with a few parts also.

Mini-MosFet Audio Amplifier 30W by IRF530-IRF9530

Power Amplifier Parts:
R1_______________2K2 1/4W Resistor
R2______________27K 1/4W Resistor
R3,R4____________2K2 1/2W Trimmers Cermet or Carbon (or 2K)
R5_____________100R 1/4W Resistor
R6_______________1K 1/4W Resistor
R7,R8__________330R 1/4W Resistors
C1______________22µF 25V Electrolytic Capacitor
C2______________47pF 63V Polystyrene or Ceramic Capacitor
C3,C4__________100µF 50V Electrolytic Capacitors
C5____________2200µF 50V Electrolytic Capacitor
Q1____________BC550C 45V 100mA Low noise High gain NPN Transistor
Q2___________IRF530 100V 14A N-Channel Hexfet Transistor (or MTP12N10)
Q3__________IRF9530 100V 12A P-Channel Hexfet Transistor (or MTP12P10)

Read more source: http://www.redcircuits.com/Page123.htm thank you.