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I left the last shots for today . My question is as follows:
The current in E2 (Follow the scheme) has a negative peak of 168.39mA at 0,05ms with a peak voltage of 8.0092V at N004 giving a 1.3307W .
The current in input 9.8mA at V1 and 24V at V1, giving a 224.49mW of power consumed .
My question is as follows:
Why does LTspice show a lower consumption value in V1 at the entrance, compared to the value displayed at the exit at E2, even if it is in a small fraction of time?
Is LTspice supposed to present this type of values, being a reference software in electronic simulation?
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Hi Nelson,
I return to your questions you asked in connection with the ultimo-funcional.asc circuit file and sreenshot
Math of input Vs Output.png and I included your shot below from your above post for reference only.
I repeated the simulation (note that I also used r=2 Ohm for L1 as you did back then) and plotted the same input and output currents and power levels you did, see 2nd attachment.
I drew a vertical yellow line at 35.5 us where the highest output power (1.3 W, red curve) manifested and where the current via E2 bulb was the highest too (-165.5 mA, dark blue curve). Here the simulator gave 210 mW (light blue curve) input power, input current taken from 24V voltage source was 8.66 mA (green curve) at the moment of 35.5 us.
These values are very close to your values, the small differences should have come from the reading accuracy of the moving cursor over the curves i.e. our own hand accuracy.
And you considered the time at 0.05 ms i.e. at 50 us but in your plot the maximum peak current in E2 is at less than 40 us time as I see it. Well this difference is no problem for me, and this does not make your questions invalid in any way.
It is also ok that you chose time range between 20 us and 260 us to display the input and output currents and power levels to illustrate your questions (I refer to your plot file again:
Math of input Vs Output.png).
Now on your 1st question: LTspice showed lower input power taken from V1 voltage source than the output power in E2 bulb was
because at that particular moment (at your 50 us or at my 35.5 us) those peak power levels must have been ruling in the simulated circuit. On your 2nd question: LTspice and other Spice based circuit simulators are supposed to present correct results provided the component models in them are close to the electrical parameters of the real world components, this depends also on the software user what he or she enters.
To further answer your 1st question, we need to
evaluate the total input power the circuit received between time range from 0 to 20 us. Notice that there is an initial condition: 8V is pumped out from C4 which kicks the oscillator in and let me show you what power and current levels are present in the same circuit within the 0 to 20 us time duration, see 3rd attachment.
The red curve shows L1 coil current, the pink curve shows voltage across L1 coil, the yellow curve shows the instanteneous peak power in L1 and the green curve shows the DC input current taken from V1 voltage source. Note that the input current is very close to zero mA during the full 20 us time duration hence the currents and power levels shown by the curves come mainly from the 8V initial voltage established in C4 by the software.
Notice that this circuit stops in the simulator at around 197.7 ms if run as long as say 200 ms. I attached the current and power level curves for the time range between 196 and 200 ms. The output power (red curve) in E2 bulb converges from
3.6 mW average power to zero, while the input power converges from
-198 mW average power to also zero, both levels are for the 196 to 200 ms time range (the power levels are received by Ctrl + left mouse clicks of course).
General notice if I may: in circuits that include capacitors and coils that oscillate at a certain (mostly at resonant) frequency, the instanteneous peak power levels may exceed the instanteneous peak input power levels taken from a voltage or current source.
Maybe I answered your 2 questions, if not please ask.
Gyula
Author
Topic: Itsu's workbench / placeholder. (Read 137176 times)
