What is the optimal time-base setting for a c.r.o display?

[Janiceleong26]

Homework Statement

How to find the time-base setting?

Homework Equations

None

The Attempt at a Solution

Firstly, I calculated the period of the revolution..
3000 Rev -> 60s
1 Rev -> 0.02s
Then, how to calculate the time base setting?

Do we need to estimate which is the most suitable one?
If the display is 10cm wide then, 0.1/0.02= 5 rev ?

 

[gneill]

Yes, estimating the most suitable one is the way to go. Work out how many cycles of the signal will appear on the display for each of the timebase settings and select one that will most distinctly show (to the naked eye) separate pulses.

 

[Janiceleong26]

Yes, estimating the most suitable one is the way to go. Work out how many cycles of the signal will appear on the display for each of the timebase settings and select one that will most distinctly show (to the naked eye) separate pulses.

Ok, thanks !

 

[andrevdh]

This is a tricky question. Obviously the slowest setting will show the most pulses, but will they appear too close together? The fastest setting might show only one pulse or only part of it. Also the pulse should go both positive and negative (volts) as the magnet passes the coil.