Discussion in 'Homework Help' started by mentaaal, Oct 19, 2008.

1. ### mentaaal Thread Starter Senior Member

Oct 17, 2005
451
0
Hey guys,

I am doing a homework problem. We have to calculate the integrator steady state error for an integrator with:

Rin = 10k
Cint = 10nF
Ib = 100nA
Vio = 2mV
Iio = 10nA

The formula for integrator errrors is:

1/RC∫Vio dt + 1/c∫Ib dt + Vio

What i have done is this: (based on a previous example given to us)

1/(10k*10nF)*2mv + 1/10nF*100nA + 2mv

But when i do this my results is like in the tens of volts! because of the first multiplication.....

2. ### mik3 Senior Member

Feb 4, 2008
4,846
63
By assuming Ib and Vio to be constant the correct expression is that:

1/(10k*10nF)*2mv*t + 1/10nF*100nA*t + 2mv

t=time in seconds

thus the error increases with time as the output does.

3. ### mentaaal Thread Starter Senior Member

Oct 17, 2005
451
0
Thats what i was thinking but i was taking notes as gospel again and not trusting my own thoughts on it. Cheers mike.