Readout Block - Tektronix 7B51 Instruction Manual

Circuit Description-Type 7B51
Magnifier. Relay K780, when energized parallels R782
with R786·R785 to increase the gain of the amplifier by a
factor of 10. R785 is adjustable for calibration of the X10
gain. Mag Regis adjustment R795 is used to balance the
output for no trace shift when switching the X1 to X10
magnification.
READOUT BLOCK
The Readout Block consists of switching resistors and a
set of contacts operated by the X 10M AG relay. The
switching resistors, selected by the setting of the Readout
Switch (part of the TIME/DIV switch), are used to signal
3-12
the Indicator Oscilloscope of the setting of the TIME/DIV
switch.
Refer to Schematic Diagram 4, Timing Switch, at the
back of the manual to find the resistors associated with a
particular setting of the TIME/DIV switch. The number 1,
2, or 5 is selected by resistors R704-R705-R706. The num-
ber of zeros is selected by resistors R711-R712-R713-R715.
The TIME sub-unit (milli, micro, or nano) is selected by re-
sistors R721-R722-R723-R724. R728-R729 select the
symbol S (seconds). R701-R702 select the symbol
>
(greater than) when the VAR TIME/DIV knob is in the out
(uncal) position. R715 is switched out by the X10 MAG to
increase the displayed readout by a factor of 10.
®