CALCULATION OF THE OUTPUT CURRENT AND VOLTAGE OF AN OPERATIONAL AMPLIFIER
Here is a new question from Online Technologies For Beginners (NPROT).
A classic circuit based on the use of an operational amplifier is assigned.
The non-inverting input is powered with a voltage V1 of 1 V, and you are asked to determine the value of the current Io and the voltage Vo at the output of the operational amplifier.
SOLUTION
It can be observed that the circuit in question is a classic configuration of a non-inverting amplifier whose gain, as known, is equal to:
By substituting the values of the resistors, the gain of the amplifier is equal to 6:
The output voltage is equal to the voltage applied to the amplifier input multiplied by the gain value:
Vo=G·V1
And therefore:
Vo=6·1 = 6V
We have therefore answered one of the two questions of the exercise.In particular, we have that the voltage measured at the output of the operational amplifier is equal to 6 Volts.
To calculate the output current, we must observe that the current entering the inverting terminal is zero.
It follows that the current Io passes through the resistor R2 and R1 in series as indicated by the arrows in the figure.
We can therefore apply Ohm’s law knowing that at the ends of the two resistors in series there is a voltage equal to Vo.
We therefore have that:
Substituting the values, we obtain that the current Io is equal to 1mA:
