Flickering LED source/specs

Discussion in 'The Projects Forum' started by ErnieM, Oct 5, 2012.

  1. ErnieM

    Thread Starter AAC Fanatic!

    Apr 24, 2011
    Does anyone have a source for a LED with an integral flicker circuit?

    I just bought a dozen flickering tea lights as I needed 8 of them for a project, along with the translucent covers. Good find, exactly what I wanted, but the next step is to place these LEDs in another circuit so I want to see some specs.

    The entire circuit inside is 3 AG13 batteries for a 4.5V source, a switch, and the the LED. No limiting resistor, but the battery voltage does change so it's using the internal battery resistance as the limit.

    All my searches either find complete lights or projects with a microcontroller. Not the discrete LED component itself.

    Does anyone have a link for these?
  2. KJ6EAD

    AAC Fanatic!

    Apr 30, 2011
  3. ErnieM

    Thread Starter AAC Fanatic!

    Apr 24, 2011
    That be it. Thanks very much.
  4. wayneh


    Sep 9, 2010
    ErnieM likes this.
  5. ErnieM

    Thread Starter AAC Fanatic!

    Apr 24, 2011
    Yup, good project. I saw that searching for info before I posted my question.

    These are going to be weird devices to control. My end use is a Hanakuh Menorah I can set up and let it automatically do it's thing for 8 crazy nights. Controller is a PIC and a real time clock chip, plus some mosfets to switch the LEDs. That much is simple, also draws approximately zero current as the PIC spends 99.9% of it's time in sleep mode.

    It's easy to over think how to control a device that has neither a fixed voltage drop or current draw, but a little experiment with some resistors off a fixed supply shows they still flicker nicely when drawing some 11 to 25 mA.

    It all comes down to how much current the LEDs use, and for how long they stay on each day. It looks like 1 hour a day for 8 days will be no problem for a bank of 3 series D cells. The load varries from 2 LEDs the first night to 8 the last night. Even using the full load every night (call it .27A) the load (5.6 ohms) is less (current) then this graph from the spec sheet:

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