Hello everyone.
I was hoping someone could just clarify the following equation for me. Here is the circuit I am working with:
The equation I am having trouble with is: V+ = VIN ∙ R2/(R1 + R2) + Vo ∙ R1/(R1 + R2)
For the calculations, I am assuming that: Vref = 2.5v, VIN = 5v, Vo = 5v, R1 = 1kΩ, R2 = 5kΩ.
I started like this:
Lower threshold: 2.5 = (X ∙ 5k / 6k )+(5 ∙ 1k / 6k) so X = 2v
The upper threshold, assuming this time that Vo = 0, is 3v. This makes sense!
The only problem is that further down in the tutorial I am reading it says:
Vth+ = - VN ∙ R1 / R2
Vth- = - VP ∙ R1 / R2
Did I not just calculate the upper and lower thresholds? 2v and 3v?
So I guess my question is: What the heck did I calculate? It seemed to make sense...
I know I should have a decoupling capacitor, and a few more improvements but for now I'm trying to understand the basic maths of it.
Thanks!!
Oh yeah, P.S. if anyone could quickly explain the function of those 2 zener diodes it would be great
I was hoping someone could just clarify the following equation for me. Here is the circuit I am working with:
The equation I am having trouble with is: V+ = VIN ∙ R2/(R1 + R2) + Vo ∙ R1/(R1 + R2)
For the calculations, I am assuming that: Vref = 2.5v, VIN = 5v, Vo = 5v, R1 = 1kΩ, R2 = 5kΩ.
I started like this:
Lower threshold: 2.5 = (X ∙ 5k / 6k )+(5 ∙ 1k / 6k) so X = 2v
The upper threshold, assuming this time that Vo = 0, is 3v. This makes sense!
The only problem is that further down in the tutorial I am reading it says:
Vth+ = - VN ∙ R1 / R2
Vth- = - VP ∙ R1 / R2
Did I not just calculate the upper and lower thresholds? 2v and 3v?
So I guess my question is: What the heck did I calculate? It seemed to make sense...
I know I should have a decoupling capacitor, and a few more improvements but for now I'm trying to understand the basic maths of it.
Thanks!!
Oh yeah, P.S. if anyone could quickly explain the function of those 2 zener diodes it would be great