Another design that uses the output transistor technology V-MOSFET. The transistors are we offer many advantages over a simple bipolar transistor, such as high speed, thermal stability, low distortion, etc.
The use of diodes D2 until D5 in combination with the resistances R17-19, they protect the gates of transistors v-fet from exceeds the voltage ± 14V and it creates perforation in very thin layer SiO2, that is used as insulation in the gate. This way of protection is common in all the amplifiers that use these transistors. The total gain of amplifier is 32.6, regulated from the R18, R6 and R8, in the negative feedback. Also is used enough the use of local feedback for stabilisation of operation under all the conditions. Because the transistors v-fet have positive factor of temperature, with result with the increase of temperature is increased also their resistance. This increase has as result the reduction of current that via the transistor, hence also his power. The use of separated supply in the stages of drive and exit, ensures stability and reject of distortion of intermodulation.
Series of VMOS FET POWER [ 2SK134 or 2SK135 ] [ 2SJ49 or 2SJ50 ], they are that, more above transistor they are not produced more by the Toshiba and are enough difficult they are found henceforth. They can be replaced with [ 2SK1530 in the place of 2SK135 ] and [ 2SJ201 in the place of 2SJ50 ]. The new transistors are in plastic case ΤΟ-3Ρ and no TO-3, bear in bigger supply of operation and have positive factor of temperature. This mean that with the increase of temperature, is increased and the current that is gone through from through the transistor. The new transistors him I have still not tryed and me it would interest to learn if somebody him used also with which results.
The use of diodes D2 until D5 in combination with the resistances R17-19, they protect the gates of transistors v-fet from exceeds the voltage ± 14V and it creates perforation in very thin layer SiO2, that is used as insulation in the gate. This way of protection is common in all the amplifiers that use these transistors. The total gain of amplifier is 32.6, regulated from the R18, R6 and R8, in the negative feedback. Also is used enough the use of local feedback for stabilisation of operation under all the conditions. Because the transistors v-fet have positive factor of temperature, with result with the increase of temperature is increased also their resistance. This increase has as result the reduction of current that via the transistor, hence also his power. The use of separated supply in the stages of drive and exit, ensures stability and reject of distortion of intermodulation.
Series of VMOS FET POWER [ 2SK134 or 2SK135 ] [ 2SJ49 or 2SJ50 ], they are that, more above transistor they are not produced more by the Toshiba and are enough difficult they are found henceforth. They can be replaced with [ 2SK1530 in the place of 2SK135 ] and [ 2SJ201 in the place of 2SJ50 ]. The new transistors are in plastic case ΤΟ-3Ρ and no TO-3, bear in bigger supply of operation and have positive factor of temperature. This mean that with the increase of temperature, is increased and the current that is gone through from through the transistor. The new transistors him I have still not tryed and me it would interest to learn if somebody him used also with which results.
List Componet
R1=27Kohm
R2-11=4.7Kohm
R3-4=5.6Kohm
R5=47Kohm
R6=1Kohm
R7-10-21=22Kohm
R8=12ohm
R9=1Mohm
R12=33ohm
R13-20=82ohm
R14=33ohm
R15=2.7Kohm
R16=270ohm
R17-19=680ohm
R18=33Kohm
R22-23=0.33ohm 5W
R24=8.2ohm
R25=10ohm 1W
TR1=470ohm trimmer
TR2=4.7Kohm trimmer
C1=1uF 63V mkt
C2=1nF 100V*
C3=100uF 16V
C4=100nF 100V*
C5-7=22uF 16V
C6=4.7pF ceramic
C8=47uF 16V
C9=1nF 100V*
C10-11=100uF 100V
C12-14=100nF 250V mkt
C13=150nF 100V mkt
C15=100uF 35V
D1=12V 0.5W Zener
D2.....5=8.2V 1W Zener
L1=20 turns 0.6mm on R25
Q1-2=BC 547
Q3=2N5460 fet
Q4-5=MPSA93
Q6-8-11=BC182
Q7-10=MPSA43
Q9=BC212
Q12=2SK134 or 2SK135
Q13=2SJ49 or 2SJ50
