Monroe-electronics NanoCoulomb Meter - model 284 Manuel d'utilisateur télécharger pdf (Page 6)

Page 4 284.CBSM-12/98-RCA

Section 4

CALIBRATION CHECK

The purpose of this section is to provide the operator of the Monroe Electronics

Model 284 Nanocoulomb Meter with a means of verifying that overall calibration

of the instrument is within the specified limits (±2%).

Method 1:

Procure a calibration capacitor. It should be a polystyrene or polypropylene

capacitor with a precisely known value of approximately 10nF (0.01µF) (Mallory

SX-110 or equivalent).

With the capacitor charged to exactly 1.00 volt and then discharged directly into

the input terminal (BNC connector) or between the inner and outer parts of the

Faraday cup, a meter reading equal to the capacitor value (±2%) should appear

on the Digital Panel Meter (DPM) set to the 20-nCoulomb range.

Charging the calibration capacitor to 10.00 volts and then discharging it into the

input should produce a DPM reading of ten times the capacitor value (±2%) on

the 200-nCoulomb range.

It is important to handle the calibration capacitor very carefully. Do not

hold the

capacitor by its body or discharge it by touching both leads with the fingers. Hold

the capacitor by one lead only

. Use a clip-lead connected between the GND jack

and this lead of the capacitor to maneuver the other lead of the capacitor

between the “hot” side of the charging source and the input terminal.

Method 2:

Use a secondary standard charge source such as a Keithley Model 263

Calibrator/Source, following manufacturer’s instructions.

Incorrect DPM readings indicate a need for calibration.

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Monroe-electronics NanoCoulomb Meter - model 284 Manuel d'utilisateur Page 6