SECTION 111
THEORY OF OPERATION
3-1 GENERAL CONTENT The complete Vertical Amplifier circuit is
in three separate parts: the final amplifiers,
located on the upper board; the intermediate
This section contains a brief description of amplifiers on the lower board on the instru-
the overall operationof the 150A Oscilloscope, ment chassis, as shown in Figure 3-2, the
descriptions of each major section and de- input-preamplifier attenuators, phase invert-
tailed explanations of the Feedback Integrator ers and beam positioners are on the etched
Sawtooth Generator andSchmitt Trigger. The board in the Vertical Amplifier Plug-In Unit.
description for each major section is sup- All connections to the plug-in unit are made
ported by its complete schematic diagram, through two multiple-contact connectors as
voltage - resistance-tube-location diagram , the plug-in is pushed into position. Power
and when necessary, a switch detail diagram, connections to the Main Vertical Amplifier
at the rear of the manual. The material in on the instrument chassis are made through
this section is as follows: a tube-socket connector, while the signal path
between the intermediate and power amplifier
3-2 Overall Operation and Circuit stages is made thrbugh the special coaxial-
Locations cable delay lines.
3-3 Synchronizing Circuit
3-4 Sweep Generator
3-5 FeedbackIntegrator and Diode b. Horizontal Amplifier - The horizontal
Switch amplifier receives the sweep voltage
3-6 Schmitt Trigger Circuits either from the HORIZONTAL INPUT jack or
3-7 Horizontal Amplifier from the internal sweep generator, amplifies
3-8 Main Vertical Amplifier it, and drives the horizontal deflection plates.
3-9 Model 152A Dual Trace Ampli- It provides attenuation of the HORIZONTAL
fier Plug-In Unit INPUT signal or MAGNIFICATION of the in-
3- 10 Calibrator ternal sweep and determines the horizontal
3- 11 Regulated Low-Voltage Power position of the spot on the screen.
s UPPlY
3- 12 Regulated High-Voltage Power
Supply
3-13 Single Sweep And Delayed The complete Horizontal Amplifier consists
Sweep Operation of the main Amplifier, and a preamplifier
(used only for external signals applied to the
HORIZONTAL INPUT connector). The pre-
3-2 OVERALL OPERATION amplifier stage includes the VOLTS /CMpor-
tion of the HORIZONTAL SENSITIVITY selec-
The simplified block diagram in Figure 3-1 tor switch and is not effective when the switch
shows the basic signal circuits in the Model is set to one of the MAGNIFICATIONpositions.
150A Oscilloscope: the Vertical Amplifier, The MAGNIFICATION circuit of the HORIZ-
Horizontal Amplifier, Sweep Generator and ONTAL SENSITIVITY selector is in the Main
Cathode Ray Tube. Horizontal Amplifier. The sawtooth sweep
is applied to the Main Horizontal Amplifier
a. Vertical Amplifier - The verticalampli- while external signals are first fed through
fier receives the input signal, amplifies the HORIZONTAL SENSITIVITY switch and
it, and drives the vertical deflection plates. the preamplifier.
It provides attenuation of the input signal;
determines the direction of spot deflection
for a given input signal polarity; determines The complete Horizontal Amplifier circuit is
the vertical positionof the spot on the screen; located on the single etched board on the left-
supplies a signal for internal synchronization; hand, swing-out chassis. Connections to the
and incorporates a 0.25 pec delay in the in- chassis are made through two tube-socket
put waveform. connectors on the board.
3 -1 |
ACEC
