Electrical and Electronic Measurements Test 7

Number of cycles of sinewave to be displayed on CRO = 2

Frequency of sinewave = 50 Hz

Frequency of time base signal = frequency of sinewave/number of cycles of sine wave

= 50/2 = 25 Hz

According to the Nyquist criterion, f_s ≥ 2f_m is required to characterize the waveform

where f_s is the sampling frequency and

f_m is the maximum signal frequency

Given sampling frequency = 10⁸ samples per second = 100 MHz

The maximum frequency (in MHz) of a signal that can be monitored DSO

Given frequency (f) = 50 Hz

Time period (T) = 1/f = 1/50 = 20 ns

For one cycle occupying four horizontal divisions,

Minimum time/div = T/4 = 20/4 = 5 ns/div

Using the five times magnifier to give 5 ns/div,

Minimum time/div setting = 5 × 5 ns/div = 25 ns/div

Velocity of electron \({V_{ax}} = \sqrt {\frac{{2e{E_a}}}{m}}\)

\({V_{ax}} = \sqrt {\frac{{2 \times 1.6 \times {{10}^{ - 19}} \times 1000}}{{9.1 \times {{10}^{ - 31}}}}} = 18.75 \times {10^6}\;m/s\)