# Time base setting of a c.r.o

1. Sep 30, 2015

### Janiceleong26

1. The problem statement, all variables and given/known data

How to find the time-base setting?
2. Relevant equations
None

3. 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 ?

2. Sep 30, 2015

### Staff: Mentor

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.

3. Sep 30, 2015

### Janiceleong26

Ok, thanks !

4. Sep 30, 2015

### 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.