Operation; General; Part 1. Preliminary Operating Instructions; Controls And Indicators - Boonton 75D Instruction Manual

CHAPTER 3
OPERATION
3.1 GENERAL,, Before performing any measurements or tests observe the instructions
in Part 1 Preliminary Operating Instructions, of this chapter, and thoroughly review the
function of each control and indicator,, During operation, refer to the applicable
equation in paragraph 1 .4 for accuracy information, especially when measuring or
testing low-Q specimens.
PART 1. PRELIMINARY OPERATING INSTRUCTIONS
3.2 CONTROLS AND INDICATORS. All operating controls and indicators on the
Model 75D are described in the following table. Reference designations are provided
to facilitate the identification of each item when referring to the schematic diagram.
Complete familiarity with the control and indicator functions is recommended before
operation of the instrument-is attempted.
Table 3. Controls and Indicators
COMPONENT
DESCRIPTION - FUNCTION
CAPACITANCE control
(C311)
MULTIPLY C switch
(S301)
Bridge balancing variable capacitor used to
measure capacitance.
Two-section dial reads capacitance in pF.
Upper dial section is calibrated in increments
of 100 with the left half of each increment
coded black and the right half coded red.
The lower section vernier dial consists of two
concentric scales calibrated in increments
of 5 which contain unit graduations with
1/5 sub-divisions. Black numbers on the
vernier dial complement the readings
obtained on the black-coded region of the
upper dial. Red numbers on the vernier dial
complement the readings obtained on the
red-coded region of the upper dial.
Rotary switch with five capacitive decade
positions. Used with the CAPACITANCE
control (above) whose reading is multiplied
by the MULTIPLY C factor. Serves to
expand the CAPACITANCE dial and to
facilitate fractional pF measurements.
75D
b-370
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