# HELP!!

Discussion in 'Electronic Design' started by vecihi, Oct 23, 2005.

1. ### vecihiGuest

hi i am new in this forum.. but this is the best place to write m
question i guess.. the problem is with the simulation of th
circuit.. its a simple bridge rectifier circuit a simple adopte
circuit actually which is supplied with 220V AC , 50Hz and out pu
with 9V DC and 300 mA ... well when i wanted to simulate it.. i
gives error such these thing

* C:\Documents and Settings\reaven\Desktop\Pspice\Schematic2.sc
Node \$N_0002 is floatin
Node \$N_0003 is floatin
Voltage source and/or inductor loop involving V_V
Circuit has errors ... run aborte
See output file for detail
Simulation aborte

thnx for your helps! good luc
Yavu
Istanbul Tec

2. ### Jim ThompsonGuest

On Sat, 22 Oct 2005 19:36:27 -0500,

Sounds like you have multiple problems.

...Jim Thompson

3. ### John PopelishGuest

What is connected to node 2?
What is connected to node 3?

If you leave one side of a capacitor unconnected, the program has no
way of deciding the initial capacitor voltage, since any charge could
be trapped in the capacitor.

If you have only one side of many other components connected to
defined voltages, some simulators complain that having an unconnected
end produces a useless component that can carry no current.
Perfect inductors can circulate infinite current when connected to
perfect DC voltage sources. Before a time simulation runs, the
initial condition must be calculated, where all currents and voltages
are assumed to be the values reached by the time they settle to steady
state. An inductor across a voltage source settles to infinite
current. If your circuit has a DC voltage source connected across an
inductor, it probably is not what you intend to simulate.

What is voltage source V1 connected to?

4. ### Jim ThompsonGuest

Now. Now. Now. If they did that us old farts would be unemployed
;-)

...Jim Thompson

5. ### Pooh BearGuest

What are you trying to simulate specifically ?

My mind boggles that ppl do this. Why not 'simulate' using a piece of
paper ?

Graham

6. ### Roger LascellesGuest

I have a simulator which gives the same waveforms as spice, but with
additional information and you can input the data in seconds. It handles
transformer voltage drop under load for you. You have to measure
transformer primary and secondary windings with an ohmmeter, then measure
no-load secondary voltage. This tool predicts real world performance
closely.

"Electro Tools" you will find the simulator as one of the simulator
"worksheets".

Roger Lascelles

7. ### Terry GivenGuest

besides, simulating a rectifier-capacitor supply using a bit of paper is
a lot trickier than you might think. Barton wrote an entire (albeit
tedious) book on the subject....and I recently saw a paper in IEEE
trans. power electronics on the topic.

Cheers
Terry

8. ### Pooh BearGuest

My mind also boggles that anyone would actually *want* to write at such
length on this topic !

In any event such matters as DC R, winding inductance and coupling are
entirely under the control of the transformer vendor ( unless *you* know how
to specify ) and no amount of simulating will change that.

I defy anyone to better the pragmatic ' suck it and see ' version of
ensuring it performs as required after doing the initial sums the good
old-fashioned way and typically revisiting the transfomer design after the
first iteration !!!

Graham

This sounds a look like "simulating" an AM receiver with a diode on paper...
almost all the introductory material you see shows the diode clipping the
negative half of some nicely modulated AM signal and feeding it into a
capacitor/load resistor detector to smooth out the variations, thus making it
"obvious" how AM diode detection works.

....if only you could buy one of those ideal diodes in the first place!

10. ### Terry GivenGuest

specs are just words. what really counts is how the actual devices
operate. This, of course, is why Deming, Juran et al go (went) on at
great length about building long-term relationships with capable,
trustworthy vendors.
why would a transformer design need multiple iterations?

If you are building say a 2.5MW multipulse rectifier, it might not be
advisable to "suck it and see", especially wrt harmonics.

Cheers
Terry