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8March2012/version 7

LEM reserves the right to carry out modifications on its transducers, in order to improve them, without prior notice

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CAS series

Output V

OUT

The output

V

typically 2 Ohms; it can drive 100 pF directly. Adding series

Rf = 100 Ohms allows much larger capacitive loads. Empirical

evaluation may be necessary to obtain optimum results.

The minimum load resistance on

V

Filtering and decoupling

Supply voltage V

C

The fluxgate oscillator draws current pulses of up to 30 mA

at a rate of ca. 900 kHz. Significant 900 kHz voltage ripple

on

V

these frequencies the power supply rejection ratio is low, and

the ripple may appear on the transducer output

V

reference

V

capacitors, but in the case of a power supply with high

impedance, it is advised to provide local decoupling (100 nF

or more, located close to the transducer).

Total Primary Resistance

In the following table, examples of primary resistance

according to the number of primary turns.

Number of

primary turns

Primary

resistance

R

Recommended

connections

1

0.24

10

9

8

OUT

IN

1

2

3

2

1.08

10

9

8

OUT

IN

1

2

3

3

2.16

10

9

8

OUT

IN

1

2

3

Application information