Created by
Created May 17, 2012
Last modified May 17, 2012
Tags behavioural-capacitor   behavioural-transformer   capacitor   charge-conservation   dc-transformer  


A demonstration of a charge conserving behavioural capacitor.
A similar circuit can be made that will implement a flux conserving behavioural inductor of a value set by the voltage on the "value" net.


Comparing charge conservation in real and behavioural capacitors.

For the real capacitor:

At T=0, C1 is charged to 1V by V1. C2 is discharged (the voltage across it = 0). At T=0.1ms, C1 is disconnected from V1. At T=0.5ms, C2 is switched in parallel with C1. As expected due to charge conservation between C1 and C2, the voltage across C1 falls to 0.5V. Simultaneously, the voltage across C2 rises to 0.5V.

For the behavioural capacitor:

At T=0, a voltage of 1V is applied across VCCScap1 by V1. At T=0.1ms, VCCScap1 is disconnected from V1. At T=0.5ms, the voltage on the V(value) control parameter net is doubled from 1V to 2V, doubling the capacitance from 1F to 2F. As expected due to charge conservation the voltage across VCCScap1 falls to 0.5V.

This circuit demonstrates that the voltage across a behavioural capacitor realised using a behavioural DC transformer changes in exactly the same way as that across the real capacitor as its capacitance is changed.

Therefore, this implementation of a behavioural capacitor conserves charge.

Simulate > Time Domain > Run Time-Domain Simulation.


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