Note:
The purpose of this apparatus is to
measure very small electrical
currents and charges. It is there -
fore very sensitive to disturbances that you
normally would neglect completely. Please
read the section “Application hints”
DESCRIPTION OF THE APPARATUS
The electrometer has on its left side input connect-
ors for current (1) and charge (2). The reading is
shown on a zero centered analogue instrument (5).
The scale goes from “-50” to “50” and is read in
connection with the setting of the switch (4). If for in-
stance the switch is set to 500 nC, the meter will
read from -500 nC to 500 nC.
During charge measurements the apparatus can be
zeroed with the switch (8).
An output is provided between the sockets (9) and
(10) for data logging or a demonstration meter. The
voltage varies between -500 mV and 500 mV,
corres ponding to meter readings between “-50” and
“50”.
The yellow/green socket (7) to the left as well as the
black socket (10) to the right are connected to chas-
sis ground.
The apparatus is driven by a 9 V battery, placed in
the holder (3).
Current measurements
The input
I
is used with the switch settings 5 pA,
50 pA and 500 pA for measuring small currents.
The current goes through a 1 G
Ω
resistor.
This results in a voltage drop in the three measuring
ranges of respectively 5 mV, 50 mV and 500 mV.
The current input is not protected against an over-
voltage larger than 1 kV (corresponding to a current
of 1 µA or 1,000,000 pA).
Charge measurements
The input
Q
is used with the switch settings 5 nC,
50 nC and 500 nC for measuring charge.
The charge measurement can be zeroed by pressing
Reset Q.
Charge is transferred to an internal 1 µF capacitor.
This results in a voltage in the three measuring
ranges of respectively 5 mV, 50 mV and 500 mV. In
connection with typical electrostatic experiments
Manual for electrometer no. 4410.30
09.12.08
Ae 4410.30
A/S Søren Frederiksen, Ølgod
Tel. +45 7524 4966
info@frederiksen.eu
Viaduktvej 35 · DK-6870 Ølgod
Fax +45 7524 6282
www.frederiksen.eu
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