7A26 Features; Installation; General Operating Information - Tektronix 7A26 Instruction Manual

7A26 Features
OPE
The 7A26 Dual Trace Amplifier plug-in unit is designed
for use with TEKTRONIX 7000-Series Oscilloscopes . The
7A26 is a dual-channel wide-bandwidth amplifier . Internal
gain and compensation circuits are automatically switched
to correspond to the setting of the VOLTS/DIV switch .
Channel 2 can be inverted for differential measurements .
Installation
Introduction
PRELIMINARY INFORMATION
The 7A26 is calibrated and ready for use as received . It
can be installed in any compartment of TEKTRONIX
7000-series oscilloscopes, but is intended for principal use
in vertical plug-in compartments . To install, align the upper
and lower rails of the 7A26 with the oscilloscope tracks and
fully insert it . The front will be flush with the front of the
oscilloscope when the 7A26 is fully inserted, and the latch
at the bottom-left corner of the 7A26 will be in place
against the front panel . See Fig . 1-2 .
To remove the 7A26, pull on the latch (which is
inscribed with the unit identification "7A26") and the
7A26 will unlatch . Continue pulling on the latch to slide
the 7A26 out of the oscilloscope .
GENERAL OPERATING INFORMATION
For single-trace operation, either of the two identical
amplifier channels can be used independently by setting the
DISPLAY MODE and TRIGGER SOURCE switches to CH
1 or CH 2 and connecting the signal to be observed to the
appropriate input . In the discussions to follow, single-trace
operations using CH 1 only apply equally to CH 2 only .
Signal Connections
In general, probes offer the most convenient means of
connecting a signal to the input of the 7A26 . A 10X
attenuation probe offers a high input impedance and allows
the circuit under test to perform very close to normal
operating conditions .
Any TEKTRONIX probe, with a readout coding ring can
be
used with TEKTRONIX
7A-series amplifier units
equipped with readout . 'The readout coding ring on the
probe connects to a circuit in the amplifier unit which
automatically corrects the readout displayed on the CRT to
the actual deflection factor at the tip of the probe being
ATIN
INSTRUCTIONS
used . For probes to be used with amplifier units with or
without readout, see the Tektronix, Inc . catalog .
Vertical Gain Check and Adjustment
To check the gain of either channel, set the VOLTS/DIV
switch to 10 mV and connect 40 millivolts, 1 kilohertz
signal from the oscilloscope calibrator to the input connec-
tor of the channel being checked . The vertical deflection
should
be exactly four divisions .
If not, adjust the
front-panel GAIN for exactly four divisions of deflection .
The GAIN adjustment is engaged by pressing in the GAIN
control knob and turning the knob with a narrow-blade
screwdriver
(see Fig . 1-3 Front
Panel Controls and
Connectors) . 'Turn
the knob clockwise, then counter-
clockwise, until the GAIN control is engaged . When the
GAIN control is engaged, the vertical deflection will change
as the knob is turned . Turn the GAIN control knob with
the screwdriver until the deflection is set to exactly four
divisions, then remove the screwdriver .
Input Coupling
The Channel 1 and Channel 2 coupling (AC-GND-DC)
switches allow a choice of input coupling methods . The
type of display desired and the applied signal will determine
the coupling to use .
The DC coupling position must be used to display the
DC component of the signal . It must also be used to display
AC signals below about 30 hertz (ten hertz with a 10X
probe) and square waves with low-frequency components as
these signals are attenuated in the AC position .
Fig . 1-2 . Release latch .
Section 1--7A26