What is a self-bias resistor?

[Arcadio]

What is a self-bias resistor?

 

[PottedMeat]

Never heard of the term. Google says its some song... the single EE reference I saw said a resistor that can change its value. Maybe a JFET or something where varying the voltage bias changes the resistance.

 

[dkozloski]

I maybe dating myself but this type of terminology is used when describing the grid bias resistor in a vacuum tube amplifier. Get some reference material on vacuum tubes and circuits.

 

[TuxDave]

So when I hear self-biasing I think of things that maintain nominal operating conditions during changing conditions.

When designing analog circuits, bias points are designed and maintained like "this wire needs to hold 2mA of current and this node over here needs to be at 1V etc...". However when the temperature of the circuit or system starts changing, device components start to behave slightly differently (resistance changes, transistors change, etc...). So "self-biasing" is more like a negative feedback where there is a component to counter the effects of change. So if there is a temperature change causing a resistor to increase resistance there is another component to help increase voltage to maintain current if needed. So my first guess is "self bias resistor" is a resistor used in negative feedback to help a circuit "self-bias"

My other guess goes along the same lines where perhaps it's just a complicated resistor and the topology allows the resistance value to be constant in the face of changing temperature. So the resistance is "self biased" as opposed to "the resistor being used to self bias something else.

 

[flyboy84]

Originally posted by: TuxDave
So when I hear self-biasing I think of things that maintain nominal operating conditions during changing conditions.

When designing analog circuits, bias points are designed and maintained like "this wire needs to hold 2mA of current and this node over here needs to be at 1V etc...". However when the temperature of the circuit or system starts changing, device components start to behave slightly differently (resistance changes, transistors change, etc...). So "self-biasing" is more like a negative feedback where there is a component to counter the effects of change. So if there is a temperature change causing a resistor to increase resistance there is another component to help increase voltage to maintain current if needed. So my first guess is "self bias resistor" is a resistor used in negative feedback to help a circuit "self-bias"

My other guess goes along the same lines where perhaps it's just a complicated resistor and the topology allows the resistance value to be constant in the face of changing temperature. So the resistance is "self biased" as opposed to "the resistor being used to self bias something else.

I think you are on the right track here. It could refer to some sort of FET (let's say MOSFET) that is operating in the triode region (and hence behaving like a resistor whose resistance depends on the drain-source voltage) that has an associated self-bias circuit.