Where is the ESR

103

00:55:43

Okay I'm having a little hard time finding the internal resistance of these components. It seems they have an infinite Q factor, and in oscillator circuits they should never decay, but I've seen decaying circuits here in EC. So let's see if I got this right. The inductor on the left has an absolute 0ohm DC resistance. In these conditions even 1aOhm would result in a 1kV voltage drop. It seems to be dropping 1kV but the time frame is too high. At 1s/s it doesn't drop any voltage. Okay for the capacitor the ESR test must be done with an AC source. So at 100MHz a capacitor of 1.59mF would have a reactance of 1uOhm. A simplified resistive voltage divider shows the exact same voltage drop as with the capacitor, thus there is no purely resistive component in the capacitor as well. And at the most left is a tuned circuit which shows some decay even if it's an insignificant one, hinting there must be ESR somewhere in the circuit. So from where does the ESR come from? 

published 9 years ago

lmccoig

9 years ago

Idea is to have capacitor at frequency where it is as "wire" and read voltage drop across capacitor. Several shown on search such as: http://everycircuit.com/circuit/6609797403115520

thebugger

9 years ago

Yeah but hurz emulates ESR here to measure it. I'm talking about ESR in EC

hurz

9 years ago

This is what I call "numeric dampening" by the simulator engine by rounding. And its related to subsampling. As slower you simulate as less dampening you get and as closer to a perfect infinite Q you are. Anyway, you never get a perfect undamped LC resonator in EC. Its just a matter of time it will die out.

thebugger

9 years ago

So the energy doesn't even dissipate, it just vanishes basically :D. That's sad, there are quite a few implications of infinite Q factor. I did notice though that transformers in EC have some resistance

hurz

9 years ago

It dissipates into numercical 'energy' ;-) BTW, thats the reason I put sometimes an additional ac source to block going to fast in simulation which then cause unwanted dampening and fail of simulation. You remember?

thebugger

9 years ago

Yeah I remember, the undersampling problem. I see it in some circuits too. Mostly oscillators have problems when undersampled

hurz

9 years ago

Any undersampled circuit makes no sense!

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.