eldo_user

Examples
Example 4—AC Analysis of a Low Pass Filter
Note
All nodes used within the subcircuit are local nodes, in that they are only referenced within
the subcircuit itself and that they do not have to correspond with the names of the nodes
outside the subcircuit.
r1 1 2 10
l1 2 3 1.3m
c1 3 0 100n
r2 4 0 50k
x1 3 4 9 amp
The above line instantiates the subcircuit x1 of type amp connected between the nodes 3, 4, and
9. As explained earlier, these nodes correspond to the nodes in, out and vdd within the
subcircuit.
vb 9 0 5
v1 1 0 ac 1
The above lines define the voltage sources in the circuit. A DC voltage source vb between the
nodes 9 and 0 of value 5V, and an AC voltage source v1 connected between the nodes 1 and 0
of value 1V.
.ac dec 10 1 1g
.plot ac vdb(3) vdb(4)
.plot ac vp(3) vp(4)
.end
The above lines indicate that an AC analysis should be performed on the circuit within the
frequency range 1Hz to 1GHz with 10 steps per decade. A dB/frequency plot of the voltage at
nodes 3 and 4 is requested, together with a phase/frequency plot at the same nodes.
1282
Eldo® User's Manual, 15.3