Timeline for 10 3W RGB LEDs in series control current
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| S Jun 3, 2015 at 16:21 | history | suggested | FarO | CC BY-SA 3.0 |
typo, grammar
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| Jun 3, 2015 at 16:19 | comment | added | FarO | Keep in mind that if you connect the LEDs directly they get the full 5V, if you use the transistor, they will get (5-Vf) volts: the transistor is not a switch that either blocks or lets the currnt go: it brings always a voltage loss. The same for MOSFETs. | |
| Jun 3, 2015 at 16:11 | answer | added | WhatRoughBeast | timeline score: 1 | |
| Jun 3, 2015 at 15:59 | answer | added | Asmyldof | timeline score: 0 | |
| Jun 3, 2015 at 15:40 | comment | added | Wouter van Ooijen | You say one red LED connected directly draws 0.4A, and 10 LEDs in parallel draw 2A. Doesn't that strike you as odd? Can your PSU realy supply 25A, or is there something wrong with your measuremenst? | |
| Jun 3, 2015 at 15:38 | comment | added | Wouter van Ooijen | I don't think your Arduino has the output oooomph to kill a TIP120 (or itself), but connecting a transistor in this way without a base resistor is bad practice. In theory either your Arduino outputs or your transistors (or both) could be damaged. | |
| Jun 3, 2015 at 15:31 | review | Suggested edits | |||
| S Jun 3, 2015 at 16:21 | |||||
| Jun 3, 2015 at 15:30 | comment | added | FarO | Is the issue present only for the red LED? have you checked the actual voltage on the Base pin of the TIP120? have you checked the voltage drop on each TIP120? can you try with two LEDs instead of only 1 or 10? have you checked the actual voltage on the 5V rail? | |
| Jun 3, 2015 at 15:28 | history | edited | Wouter | CC BY-SA 3.0 |
added 192 characters in body
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| Jun 3, 2015 at 15:15 | history | asked | Wouter | CC BY-SA 3.0 |