3B Scientific Multimeter ESCOLA2 - Manual (Page 2)

2
2. Symbol legend
Read instruction sheet
V Voltage
A Current
Moving coil galvanometer
Apparatus with electronic amplifier
DC quantities accuracy class 2
AC quantities accuracy class 3
Use in horizontal position
2
Test voltage
Use in vertical position
DC quantities
AC quantities
Needle position zero centre
“OFF” position
3. Description
The Escola 2 is a meter for use by students to
measure to measure voltages and currents
(both DC and AC quantities) in low voltage
ranges.
All measurement ranges are selected by means
of a rotary dial. Two linearised mirror scales,
graded in a 1:3 ratio, guarantee easy readability
of the measured values.
The trimmer for setting the zero point in the
centre allows the zero point to be set precisely
when it drifts electrically.
AC quantities are calibrated for a sinusoidal
waveform. Conversion and linearisation of the
measurement is achieved by half-wave rectifica-
tion (positive half-wave) using an op-amp.
The use of a robust moving coil galvanometer
and a mechanically resilient chassis also allows
for rough operating conditions.
The overcurrent protection of the Escola 2
automatically limits the power when overloaded.
After a brief cooling phase, the apparatus auto-
matically switches on again.
4. Technical data
Voltage ranges: 0.3; 1; 3; 10; 30 V AC/DC
Source impedance: 10 kOhm/V
Current ranges: 1; 10; 100; 1000;
3000 mA AC/DC
Voltage drop for current
measurements:
100 mV AC/DC approx.
Accuracy: DC class 2
AC class 3
Electrical zerocalibration: For all DC ranges
Accuracy for zero centre: Class 5
Scale length:
80 mm
Power supply: 1x 1.5 V, IEC R6 with
test function
Overload protection: Up to ± 50 V AC/DC
peak
Frequency range: 20 Hz…50Hz…20 kHz
Dimensions: 98x148x49 mm 3 approx.
Weight: 300 g approx.
5. Operation
• Switch the device on by select the desired
operating mode,
or .
• To turn off the multimeter, set the mode
switch to the off position
.
• To test the battery, set the measurement
range dial to the position
.
5.1 Current and voltage measurements
• Conduct all normal current and voltage
measurements with the operating mode
switch in the position
. This way, setting
the measurement range with the measure-
ment range dial automatically takes care of
AC/DC switchovers.
• Connect the lower measurement potential to
the left-hand socket. For DC quantities, the
positive polarity should always be connected
to the right-hand socket.
5.2 Measurements with the zero position of
the needle centred
This mode of measurement only works for the
DC current and DC voltage ranges.
• For measurements requiring the zero posi-
tion of the needle position to be centred, set
the operating mode switch to the position
.
• Before connecting the external quantity to be
measured, use the adjustment knob to accu-
rately centre the zero position on the scale.