{"id":7979,"date":"2013-07-08T08:39:44","date_gmt":"2013-07-08T15:39:44","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=7979"},"modified":"2013-08-17T14:13:34","modified_gmt":"2013-08-17T21:13:34","slug":"2013-07-08","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=7979","title":{"rendered":"2013-07-08 LED V Boost – A Decade Ago"},"content":{"rendered":"

In the early days of my LED flashlight experimentation in August of 2003 I was experimenting with LED V boost circuits and wrote up the following note.\u00a0 I don’t remember what the circuit was – might have been a Joule Thief.<\/p>\n

LED V Boost, Low V
\nInput V = 1.503V
\nInput I = 16.3 mA
\nTotal input power: 24.5 mW
\nAssumed LED V = 3.3 V
\nMeas. LED current = 4.4 mA
\nLED power = 14.52 mW
\nEfficiency = 59.3%<\/p>\n

Changed output transistor from BC337 to a BC639.\u00a0 It made no difference in current consumption or output current.<\/p><\/blockquote>\n

Apparently I was trying different transistors to see how to maximize the current and efficiency.\u00a0 It’s obvious that I didn’t have enough power to the LED.\u00a0 At that time I was using coils with a lot of turns and high resistance, probably on a toroid with low mu.\u00a0 That’s probably the reason why the circuit was not putting out much power.<\/p>\n","protected":false},"excerpt":{"rendered":"

In the early days of my LED flashlight experimentation in August of 2003 I was experimenting with LED V boost circuits and wrote up the following note.\u00a0 I don’t remember what the circuit was – might have been a Joule Thief. LED V Boost, Low V Input V = 1.503V Input I = 16.3 mA <\/p>\n

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