Transient current vs DC current

[baseball07]

Hello. I was wondering if someone can explain to me what the difference is between transient current and DC current. What are the applications of each? When is it advantageous to know one over the other? Specifically, I am talking about simulating using Cadence. Any info would be great. Thanks.

 

[JoannesPaulus]

A DC current is any current that does not change over time (unless the conditions of the circuit change due to, for instance, temperature variations, power supply changes or programming). The bias current of a differential amplifier is one such example. An AC current is a current that changes over time due to, for example, an input signal.

 

[keith1200rs]

In CMOS Digital logic there could be almost no DC current taken from the power supply - all power consumed is transient.

Keith

 

[LvW]

A DC current is any current that does not change over time (unless the conditions of the circuit change due to, for instance, temperature variations, power supply changes or programming).

I am afraid, this answer - although correct - could give rise to misunderstandings because the question was simulation related.
It is quite normal to change the dc current over time in order to get the current-voltage characteristic of a system or part (e. g. Ib-Ic for a BJT).
As far as simulation is concerned the main difference is: In TRAN simulations all frequency dependent parts (capacitor, inductor, transformer) are taken into consideration (charging effects) - opposite to dc simulation. Here, all capacitors are treated as open circuits and all inductors as a short circuit.