The document discusses the cathode ray oscilloscope (CRO) and how it can be used as a voltmeter and ammeter by connecting it across components or measuring voltage drops across resistors. It explains how to read measurements from a CRO, such as measuring time period by multiplying the distance between cycles by the time base setting. Finally, it notes that the CRO can be used to study AC waveforms, with mains electricity in Europe operating at 50 Hz and the relationship between peak and RMS voltages.

1. The Electronic Engineer’s Best Friend

2. Cathode Ray Oscilloscope
(CRO)
Display
Channel1 Channel 2
Time base
Y-gain
My tie

3.  The structure of the cathode ray tube

4.  It can be used as a
voltmeter by
connecting it across a
component.
 It can be used as an
ammeter by
measuring the voltage
across a resistor of
known value. Then
use I =V/R to get the
current.
CRO
CRO
Resistor of known value
(shunt)
R
R

5. Time Period (ms)
Peak-to-
Peak
voltage
Reading the CRO 1
To get the time period you need
to measure this distance and
convert it to time by multiplying
by the time base setting

6. Reading the CRO 2
The total height of the wave
from peak to trough is 6.4 cm
Vpk to pk= 12.8V
V0 = 6.4V
 1 cycle occupies 2.8 cm
 T = 1.40 ms = 1.40  10-3 s
 Frequency = 1  1.40  10-3 s
= 714 Hz
2.8 cm
6.4
cm
The time base controls are set at 5 ms/cm
The voltage gain is set at 2V/cm

7.  Mains electricity is alwaysAC.
 In Europe it is at a frequency of 50 Hz.
 AC waveforms have peak voltage and RMS
voltage.
 VRMS = 0.7VPk
 AC waveforms can be studied with a CRO.