I am a newbie, and I can not understand, why current of the MOS changes if I change the resistor.
Basically, why transistors so depend on load? And how I can calculate changes..
Regards,
Paddy
Electronic – Why a transistor (MOS) changes the output current (Ids) with changes of a load resistor
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Related Solutions
Without resistors, your circuit looks like
simulate this circuit – Schematic created using CircuitLab
The problem is that there is no voltage across the emitter-base of Q1, so it cannot turn on.
Take a 10 ohm resistor then measure it, it is 10 ohms. Now disconnect it (no voltage or current applied) do you think it is still 10 ohms ? Or does it have an infinite resistance now that the current is zero ?
In the same way the channel in the MOSFET can be formed when Vgb (the channel is formed by the voltage between Gate and Bulk, the source or drain are not involved in this) is large enough. Then the conductive connection between drain and source is made even when the current is zero.
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Best Answer
I guess you are aware that drrain current is function of voltage across GATE -SOURCE.
By KVL, 5V = VGS + (drain current voltage across 10KOhm) So when you change your R, the voltage across it changes which in turn affects the voltage across Gate-Source. This VGS decides Id via the resistor R.
Hope you get it.