How do you get the Frequency from a voltage/time graph?

Question

I have to measure the Frequency from a voltage/time graph (voltage on the y-axis, time on the x-asis)

How do I do this?

Also how do i determine the time at this point? (at the point of the frequency)

I think somehow you have to use the formula

Frequency = 1/peroid

Actually

How do I get the frequency from a graph that has volts per peak on the y axis, and time on the x-axis?

Answer 1

If you already have the graph, x = time, y = voltage, find the repetitive cycles, such as zero crossing or positive peak, measure time between two of those equal points at "y", divide such time from 1 (inverse), you will have frequency in Hertz.

As a better average measurement, you can measure the time for 5 or 10 cycles, divide the time from 5 or 10, or whatever you choose.

Answer 2

Measure the period between cycles.  That is the time on the X-axis between the same two points on two adjacent cycles.  You can use the positive peaks or negative peaks or midpoint going up, etc.  Just make sure it is the same point on both cycles.

Once you know the period in seconds, then 1/period will give you the frequency.