Message 25634 in TECH.WW
From: G8MNY
Date: Fri, 10 Jul 26 07:10:00 Z
Newsgroups: TECH.WW
Subject: LED Lights
Message-ID: <64572_GB7CIP>
Path: N2MH4|GB7BED|EI2GYB|GB7CIP
R:260710/0712Z 33510@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260710/0711Z 14093@GB7BED.#21.GBR.EU LinBPQ6.0.25
R:260710/0711Z 56231@EI2GYB.DGL.IRL.EURO LinBPQ6.0.25
R:260710/0710Z @:GB7CIP.#32.GBR.EURO #:64572 [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
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..
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
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
← Return to Bulletin List