Electronics - Basic Op-Amp Circuits - Discussion
Discussion Forum : Basic Op-Amp Circuits - General Questions (Q.No. 5)
5.
If the value of resistor Rf in an averaging amplifier circuit is equal to the value of one input resistor divided by the number of inputs, the output will be equal to
Discussion:
5 comments Page 1 of 1.
Roxy said:
4 years ago
Problems state that if Rf=Rin/# of inputs then Vo is ?
For an averaging amplifier, Rin is equal for all inputs and the formula for Vo is,
Vo = (-Rf)(Sum of Inputs/Rin) but since Rf = Rin/(# of inputs) then,
Vo = -(Rin/(# of inputs))((Sum of Inputs)/Rin), Rin would cancel and you would have,
Vo = -((Sum of Inputs)/(# of inputs)), which is basically an inverted(negative) average of the individual inputs.
For an averaging amplifier, Rin is equal for all inputs and the formula for Vo is,
Vo = (-Rf)(Sum of Inputs/Rin) but since Rf = Rin/(# of inputs) then,
Vo = -(Rin/(# of inputs))((Sum of Inputs)/Rin), Rin would cancel and you would have,
Vo = -((Sum of Inputs)/(# of inputs)), which is basically an inverted(negative) average of the individual inputs.
Lakshmi said:
10 years ago
Output is independent of Rf.
Suji said:
1 decade ago
If the input is the average means the output also the average amount.
Manish said:
1 decade ago
Since input impedance is very high, therefore, input current
is zero. OPAMP do not sink any current.
i(in)= i(f)
v(in) / R = - v(O) / R(f)
v(o) = - (Rf / R) v(in)
If R = Rf then v(O) = -v(in), the circuit behaves like an inverter.
is zero. OPAMP do not sink any current.
i(in)= i(f)
v(in) / R = - v(O) / R(f)
v(o) = - (Rf / R) v(in)
If R = Rf then v(O) = -v(in), the circuit behaves like an inverter.
Lov said:
1 decade ago
It's a basically comparator which compare the zero of input signal and when he got zero then he trips from one state to another state.
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