Hi guys...
I got some queries regarding this circuit..Lets go one by one....
The text says..
"Input bias current causes a slow discharge (or charge, depending on the sign of the bias current) of the capacitor. This is sometimes called "droop," and it is best avoided by using op-amps with very low bias current "
As we know that the input bias currents are the residual currents which arises due to mismatch of internal fabricated transistors and are of the order of nanoamperes (100nA for LM324)..
My queries are...
1.In comparison of the signal voltage with input bias current ,the signal voltage have much larger magnitude..in order of volts ..hence it could easily overcome the effect of the input bias currents...and the effect of input bias currents could easily be neglected...Then why the author didn't neglect these?
2.Also to contradict the harms of input bias current there is a provision of providing the dc return resistor to ground....but in this figure it is absent...else the author tells to use opamp with very low bias currents as a remedy....can't we use DC return resistor ..??
Please help...
I got some queries regarding this circuit..Lets go one by one....
The text says..
"Input bias current causes a slow discharge (or charge, depending on the sign of the bias current) of the capacitor. This is sometimes called "droop," and it is best avoided by using op-amps with very low bias current "
As we know that the input bias currents are the residual currents which arises due to mismatch of internal fabricated transistors and are of the order of nanoamperes (100nA for LM324)..
My queries are...
1.In comparison of the signal voltage with input bias current ,the signal voltage have much larger magnitude..in order of volts ..hence it could easily overcome the effect of the input bias currents...and the effect of input bias currents could easily be neglected...Then why the author didn't neglect these?
2.Also to contradict the harms of input bias current there is a provision of providing the dc return resistor to ground....but in this figure it is absent...else the author tells to use opamp with very low bias currents as a remedy....can't we use DC return resistor ..??
Please help...
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