LCR meter with overheat detectors (firewire)

[johnsmith0774]

Does anyone know why we use LCR meters on overheat and fire detectors (firewires) to measure the resistance instead of regular multimeters??

Thanks

[tpng conehead]

From memory, measuring impedance of firewire/detectors.

[BCAR Section L]

that must be a candidate for answer of the year!
LCR meter/impedance you are a real genius aren't you.

The question however was why?

[tpng conehead]

AC powered system.

[tpng conehead]

Multimeter measures the DC resistance.
LCR meter is used as the firewire/detector has an AC sensing voltage, hence need to measure the impedance.

[BCAR Section L]

the question remains.....why?

[PDR1]

A bog-standard multimeter measures resistance by applying a voltage and measuring a current. An LCR bridge measures impedance with zero current. Measuring under null conditions is more accurate, but also passing a current through a firewire is not the best way of promoting its general health and longevity.

PDR