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G8MNY  > TECH     04.03.22 09:14l 80 Lines 2800 Bytes #999 (0) @ WW
BID : 62107_GB7CIP
Read: GUEST
Subj: LED Lights
Path: IW8PGT<IZ3LSV<DB0ERF<DK0WUE<F1OYP<EA2RCF<SR1BSZ<IW0QNL<ON0AR<GB7CIP
Sent: 220304/0809Z @:GB7CIP.#32.GBR.EURO #:62107 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

From Henner DC0OS @ DB0UHI.#NDS.DEU.EU      (Updated Jul 12)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

LED at 0.6-1.5V

 ÚÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄo +
 ³      ³   ÚÄÄÄÄÄÄ¿   ³        0.6- 1.5V
 ³     1k   ³     ÚÁ¿|ÚÁ¿
 ³      ³   ³    3³ ³|³ ³10
 ³      ³   ³TurnsÀÂÙ|ÀÂÙTurns
 ³      ÃÄÄÄÙ      ³   ÃÄÄÄÄÄÄo
 ³      ³          ³ ³/      _³_  WHITE
===    ===         ÀÄ´ NPN  _\_/_ LED
 ³100   ³100         ³\e      ³
 ³ nF   ³ nF           ³      ³
 ÀÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄo -

It works down to 0.7V.
The LEDs (colours don't mix) may have an alternate connection to +ve with the
cathodes.
The current is dependant on the bias resistor, not from the number of the LED
(tested with 1 & 3). 1 kilo-Ohm let flow 30 mA. More light will give a low ohm
transistor, but not much.
The transformer was built from a choke coil with a ferrite core like dumb-bells
(thats was my Dictionary says |-| ). The 40 turns for the collector filled it
half, the other half was for the basis-turns, the wire was thinner.

The fly-back generator is not optimized, you can experiment with core, turns &
thickness of wire, or use a better transistor with more gain & more current.
Also with the resistor & capacitor. I found the items in a box down in the dark
of my work-bench. I replaced 2 of 3 cells of my lantern, & now it can swim,
I dont have to dive to the ground to get back when it fall out of the boat...

73 from Henner, dc0os
------------------------------------------------------------------------------
White LEDs are about 3V hence the voltage step up circuit needed from 1 or 2
nicad cells. But you would not want to put one on top of a pole holding up HF
Rx ant due to the possable small level QRM!

For automated garden lights..

       ÚÄÄ´>ÃÄÄÄÄÄÂÄÄÄÄÄÄÂÄÄ> +1.2V
       ³          ³    ³/e
Photo  ÃÄÄÄÄ22kÄÄÄ)ÄÄÄÄ´ PNP
Cell  _³_        _³_   ³\
---->  Ü      AA  Ü      ÀÄ1kÄ>
---->  ³    NICAD ³
       ÀÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄ

The photocell is quite conductive in no light & turns on the PNP, this allows
bias current flow to start up the inverter.
-------------------------------------------------------------------------------
LED at 11-14V

 ÚÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÂÄo +
 ³      ³        White_³_     ³ +11-14V
 ³      ³         LED_\_/_   _³_
 ³      ³   ÚÄÄÄÄÄÄ¿   ³     /_\
 ³     1M   ³     ÚÁ¿|ÚÁ¿     ³ 1N4148
 ³      ³   ³    1³ ³|³ ³10   ³ or schotky
 ³      ³   ³TurnsÀÂÙ|ÀÂÙTurns³
 ³      ÃÄÄÄÙ      ³   ÃÄÄÄÄÄÄÙ
 ³      ³          ³ ³/
===    ===         ÀÄ´ NPN
 ³100   ³ 10         ³\e
 ³ nF   ³ nF           ³
 ÀÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄo -

In this circuit 2-3 times the current flows in the LED than is taken from the
supply.



Why Don't U send an interesting bul?

73 de John G8MNY @ GB7CIP


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