Timeline for Classic multivibrator circuit and LTSpice, why is there reverse voltage on base even with diode?
Current License: CC BY-SA 4.0
17 events
| when toggle format | what | by | license | comment | |
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| Jan 8 at 6:42 | vote | accept | wsanders | ||
| Feb 14, 2021 at 16:29 | answer | added | Circuit fantasist | timeline score: 1 | |
| Feb 14, 2021 at 7:35 | answer | added | jonk | timeline score: 4 | |
| Feb 14, 2021 at 6:28 | comment | added | jonk | @wsanders I do have a model for your lamp, by the way. And it appears to work well. It's interesting to see the lamps gradually heat up and their required current declining. | |
| Feb 14, 2021 at 5:01 | comment | added | jonk | @wsanders I just read this and I know it's been a while since it was posted up. I'm not sure what the question is. (I have bags of ge-BJTs here.) Are you looking for a ge-BJT LTspice model to use? Do you need a model for an incandescent bulb? Do you want a wider pulse width, in practice, supporting 400 mA output? Do you want a design that works well? Do you want to "fix" the existing schematic or other ideas? Are you really only asking about stray inductance (you can model that)? I'm kind of lost about what the goal is here, I guess. | |
| Feb 14, 2021 at 3:36 | comment | added | Ste Kulov | @wsanders He was saying to put a label on the node, and that will rename it from an auto-generated number to whatever that label name is. Then it's much easier to match the plots to where on the schematic it is taken. In Windows, the hotkey is F4, but you can also right-click on a node and hit "Label Net". That feature should be in both versions. | |
| Feb 13, 2021 at 23:25 | answer | added | wsanders | timeline score: 1 | |
| Feb 13, 2021 at 22:39 | comment | added | wsanders | Node 4 is the anode (+) of D1. Unfortunately, Mac LTSpice cannot display node numbers on the schematic. | |
| Feb 13, 2021 at 13:32 | comment | added | a concerned citizen |
Did you check that the frequencies are the same? I'm asking because using a generic PNP model vs the only model for a Ge PNP with a bf=22 results in different waveforms (black Ge, blue PNP).
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| Feb 13, 2021 at 12:12 | review | Close votes | |||
| Feb 17, 2021 at 23:48 | |||||
| Feb 13, 2021 at 11:51 | comment | added | Andy aka | I'm baffled as to what node 004 actually is given that your text refers to it as Vcb. Put clear node names in your circuit and refer to those when plotting the waveforms. | |
| Feb 13, 2021 at 6:07 | comment | added | jonk | Incandescent bulbs cannot be properly modeled as a fixed resistance. Just keep that in mind. | |
| Feb 13, 2021 at 4:19 | answer | added | D.A.S. | timeline score: 2 | |
| Feb 13, 2021 at 3:25 | comment | added | Kevin White | The diode has capacitance the will make the voltage go negative, the capacitance of the scope will affect the measurement. | |
| Feb 13, 2021 at 3:25 | history | edited | wsanders | CC BY-SA 4.0 |
better question formulation
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| Feb 13, 2021 at 3:16 | review | First posts | |||
| Feb 13, 2021 at 8:26 | |||||
| Feb 13, 2021 at 3:15 | history | asked | wsanders | CC BY-SA 4.0 |
