Hi Eusebius, Welcome to EasyEDA. If you remove your `GND` probe then the simulation will run as expected. It's maybe not obvious but as descibed in the EasyEDA Simulation eBook, since every circuit must have a ground (GND or 0) and - unless a reference node is explicitly stated in some way - all voltages in it are measured with respect to that ground, a consequence is that it does not make sense to probe the ground node. The simulator used in EasyEDA (ngspice) is a bit rude in that it does not politely tell you that you cannot probe GND or 0: it just says that the vector of results for 0 does not exist. But that is what the error message means. :) In: Node Voltage ---- ------- vcc 5 v1#branch -0.001 `v1#branch -0.001` is a very unhelpfully labelled way of telling you what the current is drawn from V1. The `#` character identifies the measurement as being a current and not - as the column heading implies - a voltage! Sorry but error reporting in ngpsice is a bit basic. BTW: There are some issues with the table of contents in the version of the EasyEDA Simulation eBook on the website that we have not had time to fix yet so here's a more complete version: https://docs.google.com/document/u/1/d/1OWZVVFRAe_2NW3WratpkA_SGuHa5AcRow5ZRfvcoVTU/pub#h.4d34og8 Post back if you need more help.

Thanks a lot for your help and for your time.

I must just explain that the V1#branch value I pasted in above should have shown `v1#branch -0.005` I had increased the load in your example from 1k to 5k just to sanity check that the value was indeed the current drawn from V1. Sorry about any confusion.

Thanks for the clarification.