#11060
LectronFan
Moderator

Hi everybody !

The advantage of using  FET above a normal transistor is the simplicity of the circuit.

The disadvantages are a very low constant current (depending of FET type), different current depending of FET batch and low temperature stability.

But most usages, this circuit will do !

The FET, as connected in our circuit, will deliver a constant current when enough gate voltage is applied. By using a resistor between Gate and Source, the current can be set.

In its saturation zone, the current flowing from Drain to Source (IDSS) will be almost constant, hence the name constant current source.

There’s a very good article giving more details : FET as constant current source

I will explain in an upcoming experiment The Lectron thyristor module and equivalent transistor circuit (like here proposed) to make it all clear !

Till then !

Frank

 

  • This reply was modified 11 months, 1 week ago by LectronFan.
  • This reply was modified 11 months, 1 week ago by LectronFan.