Informações sobre o equipamento:

Conar Coletronics Service Inc. 255 Osciloscópio
Conar Coletronics Service Inc.
Modelo: 255
Categoria: Instrumentos de medição
Grupo: Osciloscópio
                                    The circuitry of the Model 255 oscilloscope can be divided
into four sections: the vertical amplifier, the horizontal
amplifier, the sweep generator, and the power supply. Refer
to the block diagram, Fig. 45, for the following general
description of how these sections fit together to form the
complete oscilloscope.

The vertical amplifier receives the signal to be observed by
the oscilloscope, amplifies this signal by the setting of
the VOLTS/CM switch on the front panel, and applies the
signal, in push-pull form, to the vertical deflection plates
of the cathode ray tube (crt). A sample of the vertical
signal is also made available to the sweep section for
triggering. The vertical amplifier includes controls for ac
or dc coupling, vernier
adjustment of gain, and vertical positioning of the trace on
the crt screen. This section of the oscilloscope features
high gain and wide bandwidth.

The horizontal amplifier is very similar to the vertical
amplifier, but the circuit is somewhat simplified because of
the relaxed gain and bandwidth requirements. This section of
the oscilloscope must take a sweep signal, which may be
generated by the sweep circuit or by an external source,
amplify this signal, and apply it, again in push-pull form,
to the horizontal deflection plates of the crt. The
horizontal amplifier includes controls for selection of its
signal source and for horizontal placement of the trace on
the crt screen. The Horizontal/ Trigger (H/T) Gain control
on the front panel affects the level of only the external
horizontal or trigger signal; it does not vary the width of
the trace in the internal or line sweep modes.

The external sweep input is ac coupled, but the horizontal
amplifier itself is direct-coupled to the output of the
sweep circuit for best performance at very low sweep rates.

The sweep generator section can be considered as three
subsections: the trigger generator, sawtooth generator, and
blanking subsections. The function of the trigger generator
is to convert the trigger input signal into a pulse suitable
for application to the sawtooth generator circuit. The
triggering level is adjusted with a front panel control. The
front panel Trigger Slope switch selects whether the trigger
occurs on the positive-going or the negative-going portion
of the applied signal.

The purpose of the sawtooth generator is to generate a
high-linearity sawtooth waveform for application to the
horizontal amplifier. The sawtooth generator in the Model
255 is a triggered sweep; that is, it operates only when it
is told to do so. The command to sweep comes from the
trigger generator. Once a sweep is initiated, the sawtooth
generator will ignore all further trigger pulses until the
sweep and its retrace are completed. What this means to you,
the user of the oscilloscope, is that the sweep is highly
stable and is not affected by changes in input frequency.
The use of a triggered sweep also allows horizontal
expansion of the signal to a degree not possible with
conventional recurrent sweep generators.

At the end of each sweep, during the time that the sweep
output voltage is rapidly falling toward its originating
point, the blanking amplifier applies a large negative-going
pulse to the grid of the crt. This causes the beam to cut
off and light output from the crt to cease. Since this
happens while the electron beam is being swept back to the
left side of the screen for the next sweep, the retrace line
is effectively blanked.

The power supply section of the oscilloscope supplies all
operating voltages to the other three sections. The high
voltage supply develops -2000 volts for the crt electron
gun, +220 volts for the vertical and horizontal output
amplifiers and the blanking amplifier, 6.3 volts ac for the
crt heater, and develops a regulated +5 and - 5 volts for
all other oscilloscope circuitry. In addition, one of the
transformer windings also supplies a small ac voltage for
use in the line sweep and line trigger modes.

Now that you are familiar with the overall operation of the
various sections of the oscilloscope, refer to the complete
schematic diagram on the separate insert sheet as we begin
the detailed circuit description. You will start with the
vertical amplifier.

Estes manuais estão disponíveis para os equipamentos acima:

Conar Coletronics Service Inc. -- 255 -- Manual de serviço
O nome do arquivo: Conar-9185-Manual-Page-1-Picture
Tipo manual: Manual de serviço
Páginas: 29
Tamanho: 2.94 Mbytes (3086077 Bytes)
Idioma: Inglês
Qualidade: Documento Scaned, a leitura parcialmente mal, não parcialmente legível.
Envie data:
MD5: f3cab1f0f4f1814dabced63396d32c8e
Downloads: 29 desde 05 Agosto 2017
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