G8MNY > TECH 04.05.25 08:00z 80 Lines 2800 Bytes #131 (0) @ WW
BID : 31852_GB7CIP
Subj: LED Lights
Path: ED1ZAC<ED1ZAC<GB7CIP
Sent: 250504/0746Z @:GB7CIP.#32.GBR.EURO #:31852 [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
Read previous mail | Read next mail