Hi everyone,
I'm having kind of a tough time finding info on google for this, wikipedia is a bit vague as well.
I'm wondering about noise sources from passive components. For example, I know resistors exhibit Johnson Noise (thermal) described as
S = 4kTR (units are W/ √Hz if I recall correctly)
are there any other noise sources in a resistor not covered by the johnson noise? even extremely low ones, I probably need to know about them. Especially flicker (1/f) noise, I cannot have anything with a high flicker noise characteristic.
I am also wondering about capacitors. They have a Johnson Noise as well, but anything else?
I just found a wiki article about kTC noise, which is the noise in an RC filter. Apparently R drops out, but how would alternative noise sources in both the cap and the resistor affect the noise in a filter?
I am working on making an extremely low-noise RC Low Pass filter using just one capacitor (roll off is not important). I need to pick components that give the proper corner frequency and the lowest noise, so I will be looking at the noise in different types of resistors and capacitors and trying to pick the right values for R and C while minimizing noise.
thanks
I'm having kind of a tough time finding info on google for this, wikipedia is a bit vague as well.
I'm wondering about noise sources from passive components. For example, I know resistors exhibit Johnson Noise (thermal) described as
S = 4kTR (units are W/ √Hz if I recall correctly)
are there any other noise sources in a resistor not covered by the johnson noise? even extremely low ones, I probably need to know about them. Especially flicker (1/f) noise, I cannot have anything with a high flicker noise characteristic.
I am also wondering about capacitors. They have a Johnson Noise as well, but anything else?
I just found a wiki article about kTC noise, which is the noise in an RC filter. Apparently R drops out, but how would alternative noise sources in both the cap and the resistor affect the noise in a filter?
I am working on making an extremely low-noise RC Low Pass filter using just one capacitor (roll off is not important). I need to pick components that give the proper corner frequency and the lowest noise, so I will be looking at the noise in different types of resistors and capacitors and trying to pick the right values for R and C while minimizing noise.
thanks