Timeline for What exactly is a current source?
Current License: CC BY-SA 3.0
11 events
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| Jun 23, 2022 at 13:30 | comment | added | clabacchio | @johnywhy of course it's not ideal, but the concept is that, on one leg, you have a fixed load, such as a resistor. That creates a stable and arbitrary current on the collector of the transistor; this current is mirrored on the other leg at least approximately independent on the load. | |
| Jun 22, 2022 at 15:02 | comment | added | johny why | @clabacchio "protecting from load-induced variations" - But your answer states "you can't know the voltage over that source" - doesn't that mean the mirror voltage isn't protected from load variation? | |
| Jun 21, 2022 at 8:43 | comment | added | clabacchio | @johnywhy it's because the mirror decouples your constant current source and the load, protecting from load-induced variations | |
| Jun 9, 2022 at 15:33 | comment | added | johny why | @stevenvh Then why have two legs? If the constancy depends on the first leg, then why not just use the first leg as your current source? What does the second leg give you that you don't get with the first leg alone? | |
| Mar 22, 2012 at 16:17 | history | edited | clabacchio | CC BY-SA 3.0 |
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| Mar 22, 2012 at 15:50 | comment | added | clabacchio | @stevenvh Right, I was about to write about biasing, then I forgot :) | |
| Mar 22, 2012 at 15:49 | history | edited | clabacchio | CC BY-SA 3.0 |
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| Mar 22, 2012 at 15:43 | comment | added | stevenvh | A current mirror in itself is not a current source; the current in one leg depends on the current in the other leg. If that's not constant you don't have a constant current source. | |
| Mar 22, 2012 at 15:41 | comment | added | Green Noob | Is this the current source that textbooks mean when they say - "Consider a current source in series with etc etc"? They introduce current sources very early in the text without clearly explaining how a practical one is constructed. A beginner will have no idea how a transistor or Op-Amp work. Can you clarify? | |
| Mar 22, 2012 at 15:29 | history | edited | clabacchio | CC BY-SA 3.0 |
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| Mar 22, 2012 at 15:22 | history | answered | clabacchio | CC BY-SA 3.0 |