PTC Thermistors, Overload Protection
For Instrumentation
2322 66. 93034_93113
Vishay BCcomponents
www.vishay.com
For technical questions contact: nlr.europe@vishay.com
Document Number: 29072
170
Revision: 10-Oct-03
FEATURES AND BENEFITS
Fast response time for rapid protection
Automatic resetting once overload is removed
No contacts to burn out
No thermal runaway
Operates on DC or AC voltage
Small size and rugged construction; see Component
Outline drawing.
DESCRIPTION
Test and measuring instruments, such as oscilloscopes and
digital multimeters, can be easily damaged
if excessive voltages are applied across their input terminals.
Simple and effective overload protection can be provided by
connecting a high-voltage PTC thermistor in series with the
instrument; see Typical connection of the PTC thermistor for
digital multimeter protection drawing. Under normal
conditions, the resistance of the PTC thermistor is low, so the
test voltage will be measured by the instrument. Under an
overload condition, the PTC thermistor will switch to its
high-resistance state, absorbing the overload current and
protecting the instrument. When the overload is removed,
the PTC thermistor will return to its low-resistance state,
ready to resume its protective function.
ELECTRICAL DATA AND ORDERING INFORMATION
Note
1. These PTCs can handle maximum voltage without series resistance.
NON-TRIP
CURRENT
(RMS VALUE)
at 25
C
(mA)
TRIP
CURRENT
(RMS VALUE)
at 25
C
(mA)
NOMINAL
RESISTANCE
at 25
C
(
)
MAXIMUM
(1)
VOLTAGE
(V)
INSULATION
VOLTAGE
(V)
CATALOG
NUMBER
10
20
1600
300
600
-
2322 660 93034
10
50
400
100
600
>
1000
2322 661 93113
PHYSICAL DIMENSIONS
in millimeters
H
L
D
MAX.
T
MAX.
F
d
MASS
(g)
SPQ
PQ
CATALOG
NUMBER
30
3
20
3
5
4.5
5.08
0.6
0.47
500
10000 2322 660 93034
15.5
1.5 3.1
0.5
10
6.5
8.12
0.8
1.82
500
10000 2322 661 93113
MECHANICAL DATA
in millimeters
CCB832
T
D
F
L
H
d
For dimensions, see Physical dimensions table.
Component outline.
2322 66. 93034_93113
PTC Thermistors, Overload Protection
For Instrumentation
Vishay BCcomponents
Document Number: 29072
For technical questions contact: nlr.europe@vishay.com
www.vishay.com
Revision: 10-Oct-03
171
MSB392
V
A
input
PTC
thermistor
INSTRUMENT
10
3
MLD319
10
2
10
1
1
10
10
2
I
(mA)
V (V)
RMS
RMS
TYPICAL CONNECTION OF THE PTC
THERMISTOR FOR DIGITAL
MULTIMETER PROTECTION.
TYPICAL CURRENT/VOLTAGE
CHARACTERISTIC for 2322 660 93034.
TYPICAL RESISTANCE/TEMPERATURE
CHARACTERISTIC for 2322 660 93034.
CCB915
10
4
10
5
10
2
10
3
10
6
10
9
0
50
100
150
200
250
R
()
T (C)
10
8
10
7
1.5 V (DC) max.
550 V
pulse
TYPICAL RESISTANCE/TEMPERATURE
CHARACTERISTIC for 2322 661 93113.
CCB916
10
4
10
5
10
2
10
3
10
6
10
9
0
50
100
150
200
R
()
T (C)
10
8
10
7
1.5 V (DC) max.
375 V
pulse
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