60W AMPLIFIER MOSFET IRFP240-IRFP9240
The supply rails prudentially voltage was kept at the rather low value of + and - 40V. For those wishing to experiment, the supply voltage rails could be raised to + and - 50V maximum, allowing the amplifier to approach the 100W into 8 Ohm target.
Note:
- A small, U-shaped heatsink must be fitted to Q6 & Q7.
- Q8 & Q9 must be mounted on large heatsinks.
- Quiescent current can be measured by means of an Avo-meter wired in series to the positive supply rail and no input signal.
- Set the Trimmer R10 to its minimum resistance.
- Power-on the amplifier and adjust R10 to read a current drawing of about 120 - 130mA.
- Wait about 15 minutes, watch if the current is varying and readjust if necessary.
List Component:
R1______________47K 1/4W Resistor
R2_______________4K7 1/4W Resistor
R3______________22K 1/4W Resistor
R4_______________1K 1/4W Resistor
R5,R12,R13_____330R 1/4W Resistors
R6_______________1K5 1/4W Resistor
R7______________15K 1/4W Resistor
R8______________33K 1/4W Resistor
R9_____________150K 1/4W Resistor
R10____________500R 1/2W Trimmer Cermet
R11_____________39R 1/4W Resistor
R14,R15___________R33 2.5W Resistors
R16_____________10R 2.5W Resistor
R17_______________R22 5W Resistor (wirewound)
C1_____________470nF 63V Polyester Capacitor
C2_____________470pF 63V Polystyrene or ceramic Capacitor
C3______________47µF 63V Electrolytic Capacitor
C4,C8,C9,C11___100nF 63V Polyester Capacitors
C5______________10pF 63V Polystyrene or ceramic Capacitor
C6_______________1µF 63V Polyester Capacitor
C7,C10_________100µF 63V Electrolytic Capacitors
D1___________1N4002 100V 1A Diode
D2_____________5mm. Red LED
Q1,Q2,Q4_____MPSA43 200V 500mA NPN Transistors
Q3,Q5________BC546 65V 100mA NPN Transistors
Q6___________MJE340 200V 500mA NPN Transistor
Q7___________MJE350 200V 500mA PNP Transistor
Q8___________IRFP240 200V 20A N-Channel Hexfet Transistor
Q9___________IRFP9240 200V 12A P-Channel Hexfet Transistor
