Help on simulating a circuit - First attempt didn't work

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Discussion Overview

The discussion revolves around simulating a circuit using various software tools, specifically focusing on the challenges faced in setting up a circuit with an IC 555 timer. Participants share their experiences, seek help with specific issues, and discuss different simulation software options.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes their initial attempt at simulating a circuit, noting that it did not animate as expected, particularly due to confusion about wiring the IC 555 timer.
  • Another participant questions the arrangement of the circuit in the simulation software, suggesting that it may have led to misconnections, particularly with the power supply for the IC.
  • Concerns are raised about the version of the IC 555 timer available in the simulation software, with one participant noting discrepancies in the number of outputs and labeling.
  • Participants discuss alternative simulation software, with suggestions including LTSPICE, and express the need for specific models for the NE555 timer.
  • Errors encountered during simulation in LTSPICE are highlighted, including missing definitions for various components and warnings about floating nodes.
  • One participant shares a schematic that received positive feedback from a professor but still encounters errors when attempting to run the simulation.
  • Another participant points out issues with wiring, questioning the purpose of unconnected wires in the circuit schematic.

Areas of Agreement / Disagreement

Participants express various challenges and uncertainties regarding circuit simulation, with no consensus on the best approach or solution to the issues raised. Multiple competing views on software options and circuit configurations remain evident.

Contextual Notes

Participants mention limitations in the simulation software regarding the availability of specific components and the arrangement of pins, which may affect their ability to accurately simulate the circuit. There are also unresolved issues related to floating nodes and missing component definitions in LTSPICE.

Who May Find This Useful

This discussion may be useful for students or hobbyists working on circuit simulation projects, particularly those using the IC 555 timer and seeking guidance on software tools and troubleshooting common issues.

sampsoninc916
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Homework Statement



The assignment for me is to simulate a circuit. I've already selected a project and I have already gathered parts thanks to my parents, but I need help on simulating the circuit. My first attempt did not go so well. The final steps of the project is to build the project on a breadboard, which I can do with my dad, and build it on a perf board, which I can do with my dad as well.

Here's the app I am using to simulate the circuit:

http://www.falstad.com/circuit/

Here's the circuit I'm supposed to simulate:

Information about the circuit

The Circuit

Homework Equations



I just need to build the circuit, there really is no relevant equations as this is a project for assembling a circuit, not some help on homework or studying for a test.

The Attempt at a Solution



Here's my first attempt at doing the circuit:

http://l.bitcasa.com/C4FVbXxJ

It did not work out so well because it did not become animated, like it was supposed to have simulated electricity flowing through it.

May you please help me on my second attempt to simulate the circuit. I believe the root of my problem is not understanding where what specific wires were supposed to go inside the IC1 555 Timer. I need to simulate the circuit by the end of this weekend.
 
Last edited by a moderator:
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sampsoninc916 said:

Homework Statement



The assignment for me is to simulate a circuit. I've already selected a project and I have already gathered parts thanks to my parents, but I need help on simulating the circuit. My first attempt did not go so well. The final steps of the project is to build the project on a breadboard, which I can do with my dad, and build it on a perf board, which I can do with my dad as well.

Here's the app I am using to simulate the circuit:

http://www.falstad.com/circuit/

Here's the circuit I'm supposed to simulate:

Information about the circuit

The Circuit

Homework Equations



I just need to build the circuit, there really is no relevant equations as this is a project for assembling a circuit, not some help on homework or studying for a test.

The Attempt at a Solution



Here's my first attempt at doing the circuit:

http://l.bitcasa.com/C4FVbXxJ

It did not work out so well because it did not become animated, like it was supposed to have simulated electricity flowing through it.

May you please help me on my second attempt to simulate the circuit. I believe the root of my problem is not understanding where what specific wires were supposed to go inside the IC1 555 Timer. I need to simulate the circuit by the end of this weekend.

Why did you re-draw the circuit in such a strange arrangement? In addition to being very hard to read, it looks like you have mis-connected several things, including the power supply connection for the IC.

I'd recommend that you draw the circuit in the simulation software exactly as it is shown in the example schematic.
 
Last edited by a moderator:
The simulation software only had an IC 555 timer that had 7 outputs, and they weren't even numbered, whereas the example schematic had 8 outputs and were numbers. Can you recommend me a circuit simulation software that can do just that? Why 7 and not 8? Why the strange th, tr, ctl, labels? Why couldn't they be numbered to make it easier for me?
 
sampsoninc916 said:
The simulation software only had an IC 555 timer that had 7 outputs, and they weren't even numbered, whereas the example schematic had 8 outputs and were numbers. Can you recommend me a circuit simulation software that can do just that? Why 7 and not 8? Why the strange th, tr, ctl, labels? Why couldn't they be numbered to make it easier for me?

You could try the free version of LTSPICE:

http://www.linear.com/designtools/software/?gclid=CK3A6-eS7b0CFUFrfgodrDcApg#LTspice

:smile:
 
I can't find an IC1 NE555 Timer in LTSPICE. May you please help me find it?
 
sampsoninc916 said:
I can't find an IC1 NE555 Timer in LTSPICE. May you please help me find it?

Hmm, that's unfortunate. Try doing a Google search for NE555 spice model...
 
sampsoninc916 said:
I am working with a spice model for NE555, but it looks like this:

http://en.wikipedia.org/wiki/File:555_Pinout.svg

Instead of this:

http://www.circuitstoday.com/wp-content/uploads/2011/04/water-level-controller-circuit.png


I can't find a NE555 spice model timer with that specific arrangement of the numbers 1-8. May you please help me?

Those two pinouts look the same to me. Check out the datasheet for the NE555, and it will probably show the circuit connections that you have in your example circuit.
 
Where are the relays in LTSPICE? Here's what I currently have with building the circuit schematic:

http://l.bitcasa.com/s7LnX-v3 May you please help me?
 
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  • #10
There are many circuit simulators online. Falstad's seems too "experimental" to what you need.
LTSpice, as suggested should do just fine.
You could teach yourself a bit about it first. Check out some YouTube tutorials for it.
Maybe this link can help you:
http://forum.allaboutcircuits.com/showpost.php?p=526887&postcount=2
You may need to download some models to build what you want. LTSpice is not so fully-featured from start.
 
  • #11
I did the circuit in LTSPICE, but here's the schematic of my circuit, which the professor said looks good:

http://l.bitcasa.com/X-bpPMWt

But here is the error dialog that pops up whenever I try to run the simulation:

Circuit: * C:\Users\user\Documents\waterlevelcontrollercircuit.asc

Error on line 4 : q4 n007 n021 n016 0 bc546
Unable to find definition of model "bc546"
Error on line 7 : q5 n017 n018 n019 0 pn2222
Unable to find definition of model "pn2222"
Error on line 8 : q6 n019 n022 n020 0 pn2222
Unable to find definition of model "pn2222"
Error on line 13 : d4 n020 n007 1n4007
Unable to find definition of model "1n4007"
Error on line 20 : d3 n005 n011 led
Unable to find definition of model "led"
Error on line 21 : q3 n011 n015 n007 0 bc546
Unable to find definition of model "bc546"
Error on line 24 : d2 n004 n006 led
Unable to find definition of model "led"
Error on line 25 : q2 n006 n012 n007 0 bc546
Unable to find definition of model "bc546"
Error on line 28 : d1 n003 n009 led
Unable to find definition of model "led"
Error on line 29 : q1 n009 n014 n007 0 bc546
Unable to find definition of model "bc546"
WARNING: Node U1:N003 is floating.
WARNING: Node NC_03 is floating.

WARNING: Less than two connections to node NC_01. This node is used by V1.
WARNING: Less than two connections to node NC_06. This node is used by R3.
WARNING: Less than two connections to node NC_07. This node is used by R2.
WARNING: Less than two connections to node NC_08. This node is used by R1.
Direct Newton iteration for .op point succeeded.
Singular matrix: Check node nc_02
Iteration No. 2
Fatal Error: Singular matrix: check node nc_02
Iteration No. 2

This circuit has floating nodes.May you please help me with this?
 
Last edited by a moderator:
  • #12
You have many wires simply hanging by. What did you try to do? What should those dead-ends be doing?
 

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