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Model BSR Series

MODEL BSR SERIES

Thick Film

2512 Surge Resistors

NEW PRODUCT

APPLICATIONS

Telephone lines are often subject to a variety of voltage

disturbances which fall into two main categories -

short duration, high voltage transients caused by

lightning strikes and longer duration, over voltages

which may be caused by direct connection to main

power lines. The advent of electronic switching has

meant that sophisticated methods of protection against

these two fault conditions has to be incorporated to

ensure that potential damage is limited.

The two types of protection are: primary, which

attempts to deal with the bulk of the energy from a fast

transient, particularly lightning strikes and power

crosses and secondary, which provides a further level

of protection to prevent damage to sensitive electronic

circuits.

The possibility of disturbances in the line is dependent

on the environment of the equipment installation. In

the case of a PABX, where the telephone line, terminal

equipment and the line interface are all installed in the

same building, the possibility of induced lightning

transients is greatly reduced and the opportunity for

damage induced by direct connection to mains is low.

For these reasons the degree of protection is much less

than for equipment connected outside the building

where the risk increases dramatically.

BI Technologies is involved in secondary protection for

all types of environment. The BSR Series has been

specifically designed for PABX where cost is of

paramount importance. For central switches, the tip

and ring resistors are expected to perform identically to

maintain the correct resistance for a balanced line

system. Both resistors are therefore generally

produced on a common substrate, which may be

through hole or surface mount, and perform close to

one another under all foreseeable fault conditions in

both common and differential modes. For PABX,

tracking is not required because an individual resistor

is used which normally runs at low power yet has the

ability to withstand considerable power for long

periods and has good characteristics under high

voltage transient conditions.

The BSR Series is a surface mount chip resistor

in a standard 2512 package which utilizes special

resistor film to handle the high voltage with

FEATURES

• 1.2/50 microsecond 250V pulse

• 10/700 microsecond 250V pulse

Specifications subject to change without notice.

• Nickel barrier terminations

• Double glass passivation

Continued . . .

Contact factory for custom surge resistors meeting

Bellcore testing conditions.

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