Transistor as a resistor

[transign]

How I could use a simple mosfet as a resistor instead of using a big resistor of 20MΩ ? How should I bias and connect it to my topology?

Thanks!

 

[danadakk]

https://www.edn.com/a-guide-to-using-fets-for-voltage-controlled-circuits-part-1/

Above might help....


Regards, Dana.

 

[stenzer]

Hi,

do you really need a MOSFET acting as a 20 M\[\Omega\], or do you need to limit the current in some way?

RB

 

[crutschow]

For a fixed 20MΩ it's much easier to use a resistor.

 

[Audioguru]

20 Million ohms or 20 milli-ohms (0.02 ohms)?

 

[transign]

it's for an RC filter and I want to reduce the area used

 

[stenzer]

Hi,

you know there are very tiny SMD components available e.g. 0201 or 0402, which is way smaller than a transistor. Which kind of current/power has this filter to withstand? I reckon you are aiming to use THT components, is that right?

BR

 

[Audioguru]

If you measure and adjust a resistor to bias a transistor to be used as a resistor then the resistance of the transistor will change if the supply voltage changes (a battery voltage running down) and if the temperature changes (as it warms up when turned on or the ambient temperature changes).