How can we measure voltage between two points to write expression in behavioral voltage source?

[prajapatisantlal]

I writing an expression in a subcircuit with pyspice as V(x,y) where x and y are two nodes. How to fix it?

[benedictjones]

It is quite hard to understand exactly what you are asking? Can you give an example?

The first thing that came to mind for me is the expressions you might write for a B source. For example, a step function:

Consider two nodes "in" and "out". Lets write out current defined equation (in this case an if statement) based on the voltages at these nodes: i_express = "((v(in)-v(out))>0) ? 1 : 0" # i.e., if V(in,out) > 0 then i=1, else i=0 Now, we use this to define the current of the B source component: self.B('myB1', 'in', 'out', i=i_express)

As far as I remember, when writing in the raw spice (which is what you are basically doing here) the voltage between two nodes is not defined as V(x,y) but as v(x)-v(y). Though you can look at the NGSpice manual to check this. I hope this helped?

[santlal123]

Thank you benedictjones. I exactally want this.