2 Application
The programmable low-voltage power supply unit PN 300 is an efficient triple power source.
Sources A and B can supply voltages from 0 to 30 V in steps of 10 mV and currents from
0 to 2.3 A in steps of 1 mA.
The settings accuracy of the output voltage of both sources is 0.05 %. The interference
voltage at the output terminals is less than V
rms
= 1 mV.
The sources can be used independently (A and B) or in parallel connection (A + B). As the
outputs have no ground connection, loads with voltage potentials up to 250 V (a.c.) can be
connected.
Moreover, the power supply unit provides a constant voltage source of 5 V/2 A (C).
The instrument is equipped with a parallel interface according to IEEE-488.2 standard (GPIB)
for measuring systems and a serial interface RS-232C for communicating with superior sys-
tems. All functions and parameters can be set, measurements can be carried out and measured
values as well as the state of the instrument can be transmitted.
3 Set-up and Functional Description
3.1 Block Diagram
115/ 230 V
+5 /
+12 V
Fan
Unit
CPU
+/ 5 V
+/ 5 V
~
=
~
=
Display
Key-
board
RS-232C
GPIB
+
_
V reg.
I reg.
I reg.
V reg.
V
I
I
V
GND ref. A
GND ref. B
Parallel Mode
Feedback
Parallel reg.
Voltage
reg.
Parallel
Mode
~
=
~
Transformer
Output A
Output B
Output C
26
1
2
3
910
4
5
11
12
8
14
23 24
25
15
16
6
17
18
19
22
20
21
13
7
D
A
D
A
+
_
5 V/ 2 A
+
+
_
+
_
A
D
A
D
A
D
A
D
6
Operating Instructions PN 300
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