E6 and E12
values are available as standard.
± 20% and ± 10% available as standard.
Range - ρ
10 Ohm cm to
5000 Ohm cm
ρ = R x A/L, where
R = Resistance Value
Temperature Coefficient - TCR
-0.15% per °C Temperature Rise depending on Resistivity
TCR = 0.16 x e
-(log ρ / 1.4) - 0.135
(% / °C Temperature Rise)
Coefficient - VCR
-0.5% to -7.5%
/ kV / cm
VCR = -0.62 x ρ 0.22
(% / kV / cm)
For ρ domain 10 to 5000 Ohm cm
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
Working Voltage levels (V
can be derived from the appropriate formulae for each Resistor Type.
Waveforms are defined in the usual manner: 1.2/50 µs indicates a rise time to peak value in 1.2 µs and an
exponential decay to half amplitude in a total time of 50 µs.
Worked example (50 Hz rms) :
Consider an SR
2825 Resistor with a Resistance Value of 100R0.
What is the
maximum 50 Hz rms Working Voltage (kV) sustainable for an insertion time
of 100 ms?
V working = 2.4
x (1.8R / t) 0.3 = 2.86 kV
(Note: R =
Resistance Value in Ohms and t = 50 Hz Insertion time in ms)
(1.2 / 50 µs) :
Consider an SR 2825 Resistor with a Resistance Value of 100R0.
What is the maximum Working Voltage (kV) for a 1.2/50
V working = 1.26R x (-1 + √(1 + 33/R)) = 19.31 kV