is it necessary to match 2sj162&2sk1058

[Nico Ras]

Here is an alternative class A and it works with 2SK1058/2SJ162.

To get an output of about 15 watts, the bias current is about 700 mA.

You need a substantial heat sink to dissipate +32 watts.

 

[umut1001]

thanks Mr Ras.. how are you i saw your other circuits too..best wishes..

 

[AndrewT]

Hi,
the Vgs of a lateral FET is much lower than a VFET at quiescent current. It is even lower than Vbe of a BJT.
At very high currents the Vgs becomes similar.

 

[umut1001]

now true measurements

i am sorry..i made a wrong measurement..now its the true one..

i have two pairs.

2sj162 : one of them is 0.8volts and the other one is 0.812 volts

2sk1058 : one of them is 0.666volts and the other is 0.670 volts

now i dont know that is it enough matched to make a high end class a or ab amplifier...what do you think?

 

[AndrewT]

Re: now true measurements

i2sj162 : one of them is 0.8volts and the other one is 0.812 volts

2sk1058 : one of them is 0.666volts and the other is 0.670 volts

@ what current?

 

[umut1001]

it is about 40ma i am not sure it is enough..what do you think..i will try 80ma

 

[AndrewT]

about 40mA is not good enough.
You MUST match using the same drain current in all devices and this preferably should equal the actual quiescent current in the finished amplifier.