Open loop gain of an operational amplifier

In summary, to determine the open loop voltage gain of an operational amplifier with AC input voltage experimentally, you must make sure the inputs are at the same voltage and use feedback at DC without producing AC feedback. Additionally, a supply voltage of +9V must be used for the op amp.
  • #1
fickle
19
0

Homework Statement



How can the open loop voltage gain of an operational amplifier with AC input voltage be determined experimentally?

Supply voltage for op amp is +9V.

Homework Equations





The Attempt at a Solution



I'm really stuck here. I would appreciate some outline of basically what I have to do so I could even make a first attempt at this.
 
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  • #2
fickle said:

Homework Statement



How can the open loop voltage gain of an operational amplifier with AC input voltage be determined experimentally?

Supply voltage for op amp is +9V.

An opamp has a very large gain with a DC input, so you must make sure the inputs
are at the same voltage if there's no input signal.

Use feedback to do this at DC without producing AC feedback.
 
  • #3


To determine the open loop voltage gain of an operational amplifier with AC input voltage experimentally, you will need to follow these steps:

1. Set up a circuit with the operational amplifier, a function generator, and a voltmeter. The function generator will provide the AC input voltage, and the voltmeter will measure the output voltage of the op amp.

2. Connect the function generator to the non-inverting input of the op amp and ground the inverting input.

3. Set the function generator to produce a sinusoidal input signal with a specific frequency and amplitude.

4. Measure the output voltage of the op amp using the voltmeter. Make sure to take note of both the amplitude and phase of the output signal.

5. Repeat this process for different input frequencies and amplitudes, making sure to record the corresponding output voltages.

6. Plot the input voltage versus the output voltage on a graph. The slope of this graph will represent the open loop voltage gain of the op amp.

7. You can also determine the open loop voltage gain by calculating the ratio of the output voltage to the input voltage for each data point.

Note: It is important to make sure that the output voltage does not saturate or clip, as this can affect the accuracy of the measurements. Additionally, it is recommended to use a high-quality operational amplifier with a high open loop gain for more accurate results.
 

1. What is the open loop gain of an operational amplifier?

The open loop gain of an operational amplifier is the gain of the amplifier when no feedback is applied. It is typically very high, ranging from 100,000 to 1,000,000, and is dependent on the specific operational amplifier used.

2. How is the open loop gain of an operational amplifier calculated?

The open loop gain of an operational amplifier is calculated by taking the ratio of the output voltage to the input voltage when no feedback is applied. This can be determined through simulation or by using a multimeter to measure the voltage difference.

3. Why is the open loop gain of an operational amplifier important?

The open loop gain of an operational amplifier is important because it determines the overall performance of the amplifier. A higher open loop gain allows for greater amplification of the input signal, but it can also lead to instability and distortion if not properly controlled.

4. How does the open loop gain affect the stability of an operational amplifier?

The open loop gain is directly related to the stability of an operational amplifier. A high open loop gain can cause the amplifier to become unstable and oscillate, leading to distortion and potentially damaging the circuit. This is why feedback is applied to control the overall gain of the amplifier.

5. What factors can affect the open loop gain of an operational amplifier?

The open loop gain of an operational amplifier can be affected by various factors, including temperature, power supply voltage, and frequency. These factors can alter the internal components of the amplifier and impact its gain, so it is important to consider them when designing a circuit using an operational amplifier.

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