A block diagram of a representative cathode-ray oscilloscope is shown in
Figure 2-2. The horizontal deflection amplifier is a high-gain resistor-capacitor-
coupled class A wideband voltage amplifier that increases the amplitude of the
horizontal input voltages and applies it to the horizontal deflection plates. The
sweep generator supplies a sawtooth voltage to the input of the horizontal
amplifier through a switch that provides an optional external connection.
Block diagram of a typical cathode-ray oscilloscope
The vertical deflection amplifier increases the amplitude of the vertical
input voltage before applying it to the vertical deflection plates. The input to
the vertical amplifier appears in magnified form on the viewing screen as a graph
of the current or voltage waveform being examined. A rear terminal block provides
direct electrical connections to the deflection plates.
These connections are
used, for example, when one is examining direct-current potentials or high-
frequency signals that would be attenuated excessively by the amplifier circuits.
The power supply provides all DC voltages for the tubes, including a high DC
voltage for the CRT.