# the loss tangent

Discussion in 'General Electronics Chat' started by vibhordabas, Mar 29, 2014.

1. ### vibhordabas Thread Starter New Member

Mar 29, 2014
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0
the loss tangent is given as tanθ=σ/εω
for a perfect conductor σ=∞. that means its loss tangent is ∞. what does this mean?
does this signify that any EM wave will completely die out if it falls on such a medium ?
and if the loss is zero in case of a perfect dielectric where σ=0,the loss can also be made zero by choosing ω=∞.
and how can phenomena of reflection from conductors be explained from this loss tangent?

2. ### wayneh Expert

Sep 9, 2010
13,624
4,416
The tan of infinity is undefined. I think you need to look at the limit as the terms approach infinity.

I think you're wrestling with the gap between ideality and real materials?

3. ### Papabravo Expert

Feb 24, 2006
11,150
2,176
Remember that tan is a periodic function. It has a zero at the origin, and an infinite number of periodic zeros at integral multiples of pi. It also heads off to infinity at all integer multiples of pi over 2. So I second the notion that you should be looking at limits.

A small loss tangent represents the deviation from ideal of a typical capacitor and is a measure of the equivalent series resistance. A large loss tangent would be a device with a little bit of capacitance and quite a bit of equivalent series resistance

Last edited: Mar 29, 2014