[LT-Spice help]Modifying properties of nodes!

Discussion in 'General Electronics Chat' started by rameez787, Aug 16, 2011.

1. rameez787 Thread Starter New Member

Aug 16, 2011
2
0
Hi All,

I am using LT-Spice to simulate a circuit based on parallel and series resistances.

I want to define additional (fixed) resistance on each node. That is, in every circuit when two components are connected there is additional contact resistance.

I want to put this contact resistance in my circuit.

Is there a way in LT-Spice to define somewhere a resistance of node itself?

Regards
Rameez
Friedrich Alexander University Erlangen

2. SgtWookie Expert

Jul 17, 2007
22,202
1,793
Not with just wire.

However, you can add an inductor, and enter appropriate inductance and parasitic values of series and parallel resistance, and parallel capacitance.

You could also use a capacitor, as it has parameters for not only capacitance, but:
Equiv. Series Resistance
Equiv. Series Inductance
Equiv. Parallel Resistance
Equiv Parallel Capacitance

3. rameez787 Thread Starter New Member

Aug 16, 2011
2
0
Thanks,

My circuit is only resistances like

r1 0 2352342 234234
r2 2352342 2342323 32423
r3 234232 7634345 34533
V1 0 7634345 0.5
.op
.end

and I calculate total resistance of circuit....

now on each node I want to put a resistance of 10ohms .... how can I put an inductor/capacitor that it does not effect the net result

4. SgtWookie Expert

Jul 17, 2007
22,202
1,793
Nodes themselves do not have any characteristics of capacitance, resistance, inductance, or any other parasitics. They are perfect zero-Ohm connections. A node can be spread all over on a schematic or in a SPICE netlist, but it is a single point.

If you want to add some parasitic resistance, you will have to add single resistors between each component connection to each node. This will result in creating new nodes between the original components and the original node.

If you only want to specify resistance, then just use a resistor.