ELECTRICAL PARAMETERS

Resistance Values

Whilst E24 values are preferred, other values are available at no additional cost.

Resistance Tolerance

20%, 10% and 5% available as standard.

Resistivity Range - ρ

3 Ohm cm to 20000 Ohm cm

ρ = R x A/L,   where R = Resistance Value

Temperature Coefficient - TCR

-0.05% to -0.15% per C Temperature Rise depending on Resistivity Value.

TCR = 0.16 x e -(log ρ / 1.4) - 0.135     (% / C Temperature Rise)

Voltage Coefficient - VCR

-0.5% to -7.5% / kV / cm

VCR = -0.62 x ρ 0.22   (% / kV / cm)

For ρ domain 10 to 7500 Ohm cm

Inductance

This is negligible (nH) and the Resistors may be described as non-inductive. In practice the inductance of connecting leads will be greater than that of the Resistors.

Maximum Working Voltages

The Maximum Working Voltage levels (V working) can be derived from the appropriate formulae for each Resistor Type.

Waveforms are defined in the usual manner: 1.2/50 s indicates a rise time to peak value in 1.2 s and an exponential decay to half amplitude in a total time of 50 s.

 

Worked example :

Consider an AB 664 Resistor with a Resistance Value of 1K0 and waveform of 10 / 1000 s.

V working = 0.0659 R x (-1 + √(1 + 1315 / R)) = 34.37 kV

 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
                     
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   Copyright HVR International Limited 2015. All Rights Reserved. This page last updated: 17 April, 2013.