# Why arbitrary dependent current source is not working at all?

I am just trying to make an AC analysis at one frecuency in a circuit. I have set an arbitrary dependent current source (bi symbol) to 3 times the current through a resistor (R1). There is current trough this resistor but the current through the arbitrary dependent current source is 0. I also tried to do the same with the current with symbol bi2 but nothing changes. Why does this happen?

I put a current dependent current source (symbol f) and it worked but i would still like to know why it didn't work? What did i do wrong?

• Similar problem, same solution. Feb 28, 2021 at 17:51
• What is "bi symbol"? Is it 'B1'? What is 'bi2'? It doesn't appear in your diagrams. Feb 28, 2021 at 18:02
• I mean ,the letter that you see when selecting the current source in the menu (when you press F2). Feb 28, 2021 at 18:08

It looks like you didn't check the link in the comments. Using currents with behavioural sources can be problematic, something officially explained in the help (emphasis mine):

Circuit element currents; for example, I(S1), the current through switch S1 or Ib(Q1), the base current of Q1. However, it is assumed that the circuit element current is varying quasi-statically, that is, there is no instantaneous feedback between the current through the referenced device and the behavioral source output. Similarly, any ac component of such a device current is assumed to be zero in a small signal linear .AC analysis.

The solution is to use the CCCS (current controlled current source), and for that you need a current probe, historically chosen to be the zero-valued voltage source: Vr (no value defaults to zero). An extra node/element is a minor price to pay (as is following a link) to achieve results:

Note: be careful of the direction of current, it will always be from the positive terminal to the negative one.

• yeah, i just read it, thank you Feb 28, 2021 at 18:46