Re: EOL Resistor

Telkom wrote:
plse send me a circuit of a op amp used in a end of line resistor
in a alarm system

Eeyore wrote:
Uh ?

The typical burglar alarm system uses a series of switches
or "contacts" in a "protective loop" (a "Positive loop").
Anything that open the loop switch sets off the alarm.
The resistance of the loop can also vary widely
(think: long runs of thin wire; lead foil applied to glass).

High-security systems (e.g. UL-compliant) run a second loop
(a "Negative Loop") alongside the first loop.
No contacts are allowed in the negative loop.
Both of those loops are "supervised";
you can tell when there is a fault.

In addition, shorting the Positive Loop to the Negative Loop
(a Panic Button or an attempt to bypass the system)
will also also set off the alarm.

Fire alarms are designed to be activated when a sensor _closes_.
As such, those loops are NOT inherently supervised.
An End Of Line resistor is used to add that.

The OP needs to specify the electrical parameters of his system.
.