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Hi!, im sorry, i´m colombian and my english isnt good. I would like to know how can i note the potential difference between two points in the editor, i know that i can solve the circuit using nodes, but this voltage that program shows is between the node and ground, isnt it?, i need to know potential difference between two points, how i do that? please help me!

@sdmurciam,

Welcome to CL.

If you have two nodes (wires) in a circuit "a" and "b" then the voltage difference between them is defined by an expression like this:

V(a)-V(b)

You can use this expression to plot the voltage difference on a graph or use it in a behavioural source so that you could, for example if you used it in a current source, generate a current that is one five thousandth of the voltage difference like this:

(V(a)-V(b))/5k

or

200u*(V(a)-V(b))

You can also use the Voltage Controlled Voltage Source (VCVS) element to generate a voltage that is the difference between the voltages on each of the inputs:

For how to use the VCVS and other sources, see:

https://www.circuitlab.com/forums/modeling-and-simulation/topic/m3by7389/voltage-controlled-sources/#comment_4136

The example below shows these three ways to measure the voltage difference across a component:

https://www.circuitlab.com/circuit/x2tztc/resistor_attenuator_02/

You can also "measure" the voltage across two nodes using the voltmeter element:

https://www.circuitlab.com/circuit/f5duk6/simple-ohms-law-examples-01/

See also:

https://www.circuitlab.com/forums/analog-design/topic/b95fc6f8/can-a-voltmeter-be-given-infinite-resistance-for-education/