Inverting OP amp cutoff frequency

[pat666]

Homework Statement

1. Using the LM324 op amp build an inverting amplifier with a gain of 50.
Measure the cut-off frequency
2. Plot your results on a graph as a function of log(frequency). Comment on the
results

I have done this in a lab and then graphed it, it seems to be around 30kHz from my graph.

How can I find the exact cutoff frequency? what equation? amd also what do you think they might want me to say about 2?

THanks

 

[vk6kro]

You can read the frequency where the output voltage drops to half of what it was at 1 KHz.

Explain that this is what you did and quote the voltage drop in decibels. (dB).
This is 20 log (V1 / V2) where V1 is the half voltage point voltage and V2 is the voltage at 1 KHz. Note that V1 / V2 = 0.5.

For your comments, you could look up "gain - bandwidth product" and work out the gain - bandwidth product for your opamp.
This let's you estimate the bandwidth at other gains.