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Simulation not outputting anything on LTSpice (asc file attached)

nat3435

New Member
My group is trying to simulate a UPS for a project and this is what we came up with. First picture is the multisim simulation, second the LT spice simulation, and third it is the output. For the LT Spice simulation - What could be wrong in my circuit for having no output in my graph? Or is there a directive I missed? Did I model the LT Spice circuit differently from the multisim circuit?

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eTech

Well-Known Member
My group is trying to simulate a UPS for a project and this is what we came up with. First picture is the multisim simulation, second the LT spice simulation, and third it is the output. For the LT Spice simulation - What could be wrong in my circuit for having no output in my graph? Or is there a directive I missed? Did I model the LT Spice circuit differently from the multisim circuit?

View attachment 130981
View attachment 130982
View attachment 130983


The circuit seems to be switching Q1.
You have to click a node on the schematic to display the waveform.
 

ronsimpson

Well-Known Member
Most Helpful Member
There is 226 volts on the VCC pin of the 555. Might work in SPICE but in real life BANG! What voltage do you want?
There is no power to get to the collector of Q1.
100uH is very very low inductance to put across the power line. The transformer need to be changed. Change "u" to "m".
Change 1N4148 to 1N4007. If you really want 200+volts. If you want 12V then 1N4002 will work. Again it will not work in real life.

What are you trying to make?
 
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eTech

Well-Known Member
Adding to ronsimpson comments,
The transformer turns ratio is incorrect and the amplitude specified in the sine voltage source is incorrect.
 

crutschow

Well-Known Member
Most Helpful Member
the amplitude specified in the sine voltage source is incorrect.
To clarify, LTspice sinewave voltages are specified as the peak voltage, not RMS.

Look in the LTspice help file (F1) for "transformer".
Your LTspice transformer is shown as a step-up not a step down as you want.

Also I got a "node floating error" so I had to ground the input AC source (V1).
 
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