Chapter 8 Tutorial

Measurement Fundamentals

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precautions to maintain a “clean” high-resistance system. Test leads and fixtures are susceptible to leakage due to moisture absorption in insulating materials and “dirty” surface films. Nylon and ZfL are relatively poor insulators (10A ohms) when compared to ZdON Teflon® insulators (1079 ohms). Leakage from nylon or ZfL insulators can easily contribute a 0.1% error when measuring a 1 MΩ resistance in humid conditions. The table below shows several common insulating materials and their typical resistances.

Insulating Material

Resistance Range

Moisture Absorbing

Teflon® (PTFE)

1 TΩ to 1 PΩ

N

Nylon

1 GΩ to 10 TΩ

Y

PVC

10 GΩ to 10 TΩ

Y

Polystyrene

100 GΩ to 1 PΩ

N

Ceramic

1 GΩ to 1 PΩ

N

Glass Epoxy (FR-4, G-10)

1 GΩ to 10 TΩ

Y

Phenolic, Paper

10 MΩ to 10 GΩ

Y

 

 

 

9=8

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Image 368
HP 34970A manual Zz4 z FF, Insulating Material Resistance Range Moisture Absorbing