Timeline for Does collector feedback bias work like this in real life?
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20 events
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Oct 11, 2022 at 19:58 | comment | added | jonk | @Heroz Regarding the block diagram? I don't see any block diagram in this answer I gave. What do you mean? | |
Oct 11, 2022 at 19:57 | comment | added | jonk | @Heroz Regarding sign, I suppose I could have been clearer. But in my writing, I specifically was excluding the sign of the change and instead focusing on the magnitude of the change. So I allowed myself to change the order of the terms in the denominator of one of the expressions, without explaining that fact. If you want the sign, in that case, reverse their order. | |
Oct 11, 2022 at 7:24 | comment | added | Heroz | Sorry in your NFB diagram where did these two block from ? How did you find it? | |
Oct 11, 2022 at 7:09 | comment | added | Heroz | Here explaination: Now suppose for some reason, a temperature change perhaps, β increases. This should cause an increase in IC. An increase in IC, though, would cause an increase in the drop across RC due to Ohm's law. This, in turn, would force VC to drop. | |
Oct 11, 2022 at 7:05 | comment | added | jonk | @Heroz What website are you talking about? | |
Oct 11, 2022 at 6:57 | comment | added | Heroz | @jonk thank you very much. In website they explain in sequential events so I doubt does in reality it work like that? And I think that why they wrote in sequential events maybe because NFB diagram. So I tried to create them .And now I think in order to understand this circuit I don't need to deeply understand to guanta level right? Do you have any advice to understand circuit? | |
Oct 11, 2022 at 6:38 | comment | added | jonk | @Heroz I've seen your recent question. And I've seen you write up an NFB diagram. No, the above description isn't about using an NFB model. It can be used. I just didn't use it, here. If you want to see it, then it looks like this. There will be a LambertW() function involved in a closed solution. | |
Oct 11, 2022 at 5:44 | comment | added | Heroz | @jonk Thank you . But I have a question , explanation of this circuit they explained in sequential events. Where does this explanation come ? Is it about block diagram? | |
Oct 5, 2022 at 8:50 | comment | added | LvW | Hi jonk - thank you for this information and the links provided. | |
Oct 4, 2022 at 20:53 | comment | added | jonk | @LvW I understand the confusion. Resistance of metal conductors rises with increasing temperature and one might infer from this similar behavior for semiconductors. But the extra charge carrier production outweighs it in the case of semiconductors, I believe. I don't think any BJT has a beta that declines with increasing temperature. Theory says I shouldn't see one. See "Introductory Electronics for Scientists and Engineers," 2nd ed, 1987, by Robert Simpson or "Analogue and Digital Electronics," 1984, by H. Ahmed and P. J. Spreadbury. | |
Oct 4, 2022 at 14:02 | comment | added | LvW | Yes - you are right. I think, I must qualify my statement regarding the temperature-dependent properties of factor B (or beta). The sensitivity is very low - but there are contradictory statements regarding the sign (probably depending on the power). However, I do not have any own findings. | |
Oct 4, 2022 at 13:53 | comment | added | G36 | @LvW Are you saying that the beta does not increase with temperature? What about this figure 4 from the BC847 datasheet docs.rs-online.com/3bb0/A700000006782199.pdf And it is common to assume that with a temperature increase of 1 K, the current gain increases by about 0.5%...1%. | |
Oct 4, 2022 at 10:32 | comment | added | LvW | Hi jonk You have mentioned that beta will rise with temperature. According to my knowledge (supported by some IEEE papers) the opposite is true (but in a negligible amount). I think, the most important temperature effect comes from the saturation current in Shockleys exponential equation. However, it should be clear that Vbe does not change (automatically) but MUST be reduced externally for rising temperatures. | |
Oct 4, 2022 at 8:06 | history | edited | jonk | CC BY-SA 4.0 |
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Oct 4, 2022 at 7:57 | history | edited | jonk | CC BY-SA 4.0 |
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Oct 4, 2022 at 7:51 | history | edited | jonk | CC BY-SA 4.0 |
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Oct 4, 2022 at 7:45 | history | edited | jonk | CC BY-SA 4.0 |
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Oct 4, 2022 at 3:41 | history | edited | jonk | CC BY-SA 4.0 |
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Oct 4, 2022 at 0:55 | history | edited | jonk | CC BY-SA 4.0 |
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Oct 4, 2022 at 0:43 | history | answered | jonk | CC BY-SA 4.0 |