LT Spice Presentation-Electrical Circuital Analysis-Presentation, Slides of Electronic Circuits Analysis

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Introduction to LTSpice

Introductory Presentation on

Circuit analysis using LTSpice

Why SPICE?

•^

SPICE is an abbreviation for

S

imulation

P

rogram

with

I

ntegrated

C

ircuit

E

mphasis

•^

Analog circuit simulation has been inseparablefrom analog IC design.

-^

SPICE simulators are the only way to testcircuitry prior to integration onto a chip.

-^

Furthermore, the SPICE simulation allowsmeasurements of currents and voltages that are virtually impossible

to do any other way.

LTSpice/SwitcherCAD

• An integrated waveform viewer displays

the simulated waveforms and allowsfurther analysis of the simulation data.

• The device database, schematic editing,

simulation control and waveform analysisare integrated into one program.

• Unlike many schematic capture programs,

this one was written explicitly for runningSPICE simulations.

Tutorial

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What will you people learn in thistutorial?^ –

Drawing the circuit

Simulation

Simulation Commands

Drawing the circuit

•^

Getting the other Parts:– The next thing that you have to do is get some or all

of the parts you need.

• This can be done by
  • Clicking on the icon for a specific component;(This is good for common components such as resistors,

capacitors, etc.)

• Clicking on the 'component' button

OR

• Pressing "F2" OR• Going to "Edit" and selecting "Component..."

Drawing the circuit

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Once this box is open, select a part that you want in your circuit.This can be done by typing in the name or scrolling down the listuntil you find it.

-^

z

Drawing the circuit

• To rotate parts so that they will fit in your

circuit nicely, press "Ctrl+R" before placingthe part. If you want to reflect (or 'Mirror')the part, press "Ctrl+E".

• Upon selecting your parts, click where you

want them placed (somewhere on the greypage with the dots). Don't worry aboutputting it in exactly the right place, it canalways be moved later.

Drawing the circuit

•^

Placing the Parts:– You should have most of the parts that you need at

this point.

• Now, all you do is put them in the places that make

the most sense (usually a rectangle works well forsimple circuits).

• To move parts, click on the 'move' icon,

and then

you may select parts and drag them where you wantthem. (When you have a part selected for a move, you canrotate or reflect it as well.)

Drawing the circuit

• Repeat this until your circuit is completely

wired.

• If you want to make a node (to make a wire

go more then one place), click somewhere onthe wire and then click to the part (or the otherwire). Or you can go from the part to the wire.You should see a square block when 3 ormore wires connect at a point.

• To get rid of the pencil, right click or Press

‘Esc’

Drawing the circuit

-^

Changing the Name of the Part:–

You probably don't want to keep the names C1, C2 etc., especially ifyou didn't put the parts in the most logical order. To change the name,right click on the present name (C1, or R1 or whatever your part is),then a box will pop up (Enter New Reference Designator), where youcan type in the name you want the part to have.

-^

Please note that if you double click on the part or its value, no box willappear.

Drawing the circuit

• Using Net (Node) Labels:
  • These are important if you want to use your

own identifiers for points in the network whereyou want to determine voltages rather thanhaving to work with the node numbers thatLTSpice assigns.

• To add net labels
  • Press "F4", or• Click on the "Label Net" icon• select "Edit/Label Net" from the menu.

Drawing the circuit

• When you do this, a window will pop up where

you assign the label you want to use for thenet.

Simulation

• Before you do the simulation:
  • You have to have your circuit properly drawn

and saved.

• There must not be any floating parts on your

page (i.e. unattached devices).

• You should make sure that all parts have the

values that you want.

• There are no extra wires.–

It is essential that you have a ground inyour circuit.

Simulation

• Choosing a simulation:
  • Click on the Simulate button on the tool baror use the "Simulate/Edit Simulation Cmd"

command.