Atec Monroe-244al - Manual

ISOPROBE ®
Electr Electr Electr Electr Electrosta osta osta osta ostatic Milli tic Milli tic Milli tic Milli tic Millivvvvvolt Meter olt Meter olt Meter olt Meter olt Meter
model
244AL
Applications:
The Model 244AL is designed to function as a
general purpose materials research and evalua-
tion tool. Its unique capability for reliable, NON-
CONTACTING measurement of electrostatic
potential in the millivolt range exposes broad new
areas for exploratory research as well as provid-
ing a precision instrument for existing applica-
tions in electrostatic measurements.
Some typical and potential applications include:
• Contact Potential Measurements
• Electrophotographic Measurements
• Radiation Effects on Insulators and
Semiconductors
• Electret Measurements
• Bioelectric Potential Studies
This instrument is a basic Model 244
ISOPROBE® Electrostatic Voltmeter which has
been extensively improved to provide high speed,
low noise electrostatic measurements in the
range of ±15 volts.
Principle of Operation:
The electrostatic electrode “looks” at the
surface to be measured through a small hole at
or near the end of the probe. The chopped AC
signal induced on this signal is proportional to the
differential voltage between the surface to be
measured and the probe assembly. Its phase is
dictated by the DC polarity. This signal and a
reference signal from the oscillator are fed to a
phase sensitive demodulator whose output feeds
a DC intetgrating amplifier. The output of this
amplifier is used to drive the probe housing and
electrode to the same potential as that of the
surface undergoing measurement. The feed-
back principle and null seeking operation make a
remarkably stable and accurate instrument.
Simplified Block Diagram:
Probe Main Frame