I just started using PSPice and I don't know much circuits theory but I need to simulate this circuit and find Vout/Vin: enter image description here I did this using capture but after running simulation I get this error:

Less than 2 connections at node N01198

node N01198 is one of E1 nodes (I suppose I had to use a Voltage Controlled Voltage Source but I'm not sure). Also I changed the GAIN of E to 100000, does that work?

I tried reconnecting wires differently but it doesn't stop the error. also I don't know which type of simulation I have to try to find the frequncy response Vout/Vin. Can someone help me please I'm so confused.

my schematic: enter image description here

I'm using PSPice 9.2.


In your OrCAD schematic the voltage-controlled voltage source E1 is wired incorrectly; you've swapped the inputs and outputs. On part E1, the terminals with the circle are the part's voltage outputs.

In your OrCAD schematic the negative input terminal of the voltage-controlled voltage source E1 should not be connected to ground; it should be connected to the right hand side of resistor R2—i.e., to the circuit node that connects components C2, R2, R3, and C4. (Note that in the original figure, voltage v is the voltage drop across resistor R2; it is not the voltage from R2's left side to ground, which is how you've wired E1's inputs.)

I'm not sure why you've added capacitor C4; that part isn't shown in your original figure, and its presence alters the behavior of the original circuit—i.e., the original circuit and your OrCAD circuit are not equivalent due to the presence of capacitor C4.

If you want to run an AC analysis of the circuit (e.g., an "AC Sweep/Noise" frequency analysis), your voltage source Vin should be an AC voltage source that's compatible with AC Sweep simulations, and not a DC voltage source (VDC) which is what you are currently using. In older versions of PSpice the AC voltage source parts that should be used with AC Sweep analysis are called VAC or VSRC; in present-day versions of OrCAD PSpice you can also use a part called VSIN. For what it's worth, when performing an AC Sweep analysis, I usually set the AC voltage source's amplitude to 1 Volt for mathematical convenience (e.g., voltage gain = 20 log (Vout/Vin), and with Vin=1V this simplifies to voltage gain = 20 log (Vout)).

Also I changed the GAIN of E to 100000, does that work?

Yes. You could also specify the gain value as 100k or 100K with no spaces between the '100' and the 'k'.

One side comment. The SPICE language is case insensitive, so the units prefixes 'm' and 'M' are equivalent and both mean 'milli'—e.g., 0.001 = 1m = 1M = 1E-3. If you need to specify 'mega' (e.g., megaohm), type 'meg' or 'MEG'—e.g., 1000000 = 1meg = 1MEG = 1E6.

  • \$\begingroup\$ thanks, I used C4 because it doesn't allow me to leave it open circuit and I thought it won't make a difference if I run a DC analysis, I mean I can use it's voltage instead of Vout. Is there an other way to leave the circuit open? \$\endgroup\$ – Free Soul Jan 25 '18 at 7:25
  • \$\begingroup\$ also I tried connecting the negative input of E to right side of R2 but the error still occurs. \$\endgroup\$ – Free Soul Jan 25 '18 at 17:14
  • \$\begingroup\$ Try deleting E1 and the wires (the entire lengths) that you previously connected to E1. Then re-add E1, and re-wire the connections to E1. Before you re-wire, ensure that "snap-to-grid" is turned on in the schematic capture window. (HINT: The keyboard shortcut CTRL+T toggles the snap-to-grid feature ON/OFF. In the schematic capture window, on the upper toolbar, the snap-to-grid toolbar button turns RED when snap-to-grid is DISABLED. You want this feature to be ENABLED before you re-wire.) Also, C4 should not be needed; I can successfully simulate your circuit without C4. \$\endgroup\$ – Jim Fischer Jan 25 '18 at 19:21

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