Timeline for Why the LED stays on all the time in this very simple circuit?
Current License: CC BY-SA 4.0
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Jan 21, 2022 at 13:12 | comment | added | Andy aka | @henros I also assumed beta was 100 and, it might be more like 200 at the optimized collector current (maybe 10 mA) so, a few swings to the left are broadly countered by a few swings to the right and, maybe the LED has only 1 mA flowing. 1 mA is enough to make most LEDs look quite bright. The bottom line is that the hackaday circuit is pretty crappy hence why they use the term "hack" in their title. | |
Jan 21, 2022 at 12:40 | comment | added | user131342 | I agree completely with the conclusion, but doubt some of the calculation. Expecting a beta of 100 from a 2N2222 with a collector current of 1uA is at best optimistic - something like a 2N2484 might manage it. | |
Jan 21, 2022 at 12:20 | history | edited | Andy aka | CC BY-SA 4.0 |
added 33 characters in body
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Jan 21, 2022 at 12:08 | history | answered | Andy aka | CC BY-SA 4.0 |