flashing led

D

daron

Guest
can anyone tell me a simple way to make 1 led flash
i have a diagram for 1 led + 1 transistor + 1R
but i cant find this transistor in any shops
i have 555 timer chips but would prefer not to use them
it will be for 12 car
 
"daron" <daron69@adam.com.au> wrote in message
news:1085900701.847253@teuthos...
can anyone tell me a simple way to make 1 led flash
i have a diagram for 1 led + 1 transistor + 1R
but i cant find this transistor in any shops
i have 555 timer chips but would prefer not to use them
it will be for 12 car
Click to expand...
Just buy a flashing LED, like the Kingbright L-976 series devices. They work
off 12V.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller
 
On Sun, 30 May 2004 16:33:45 +0930, daron wrote:

can anyone tell me a simple way to make 1 led flash
Click to expand...
connect it to a battery through a resistor and a push button switch
and keep pushing the button.

i have a diagram for 1 led + 1 transistor + 1R
Click to expand...
No C? Oh, I get it. The transistor turns on and smokes the LED,
thereby flashing it once.

Way cool. I should've thought of that myself.

but i cant find this transistor in any shops
i have 555 timer chips but would prefer not to use them
Click to expand...
I'll take them off your hands.

it will be for 12 car
Click to expand...
huh? Nascar or what? What's 12 car? Viagra? DeWalt?

try a 2n2222 or 2n3904 ( I assume this POS uses an NPN transistor. )
If you can't find those in the shops, find other shops.

HTH, if not, let's have some more info like what transistor you
can't find, flash rate, and what circuit you're talking about.

But I don't recall ever seeing the circuit you to which you allude -
1 transistor, no cap. Check out:

http://www.reprise.com/host/circuits/transistor_flasher.asp

and for future:

http://www.reprise.com/host/circuits/flasher.asp

--
Best Regards,
Mike
 
Activ8 wrote...
But I don't recall ever seeing the circuit you to which you allude -
1 transistor, no cap. Check out:

http://www.reprise.com/host/circuits/transistor_flasher.asp
Click to expand...
The circuit mentions 5 to 12V supplies. But if a power supply
voltage of more than about 8V is used the two transistors may
experience high reverse emitter-base breakdown current. This
causes a severe drop in the transistor's beta, which could then
cause eventual failure of the circuit. Two resistors can be
added to solve the problem. For example, connecting each 10uF
timing cap to a tapped version of its 470 ohm resistor.

Thanks,
- Win

(email: use hill_at_rowland-dot-org for now)
 
my god clowns everywhere
thans to all that helped
anyways
i have a diagram here uses 1.2v-4.5v in to dc of ic part number HT-2014L-ND
ground of ic is ground
middle leg goes to R1 270ohm then to cathode of led
and anode of led goes to dc in of ic
i hope this makes sence
 
On Sun, 30 May 2004 21:56:50 +0930, the renowned "daron"
<daron69@adam.com.au> wrote:

my god clowns everywhere
thans to all that helped
anyways
i have a diagram here uses 1.2v-4.5v in to dc of ic part number HT-2014L-ND
ground of ic is ground
middle leg goes to R1 270ohm then to cathode of led
and anode of led goes to dc in of ic
i hope this makes sence
Click to expand...
That's an (obsolete?) Holtek IC in TO-92.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
On 30 May 2004 04:17:15 -0700, Winfield Hill wrote:

Activ8 wrote...

But I don't recall ever seeing the circuit you to which you allude -
1 transistor, no cap. Check out:

http://www.reprise.com/host/circuits/transistor_flasher.asp

The circuit mentions 5 to 12V supplies. But if a power supply
voltage of more than about 8V is used the two transistors may
experience high reverse emitter-base breakdown current.
Click to expand...
Yeah. With V_(BR)EBO at 6V and the thing getting slammed with maybe
-11 Vp...

This
causes a severe drop in the transistor's beta, which could then
cause eventual failure of the circuit. Two resistors can be
added to solve the problem. For example, connecting each 10uF
timing cap to a tapped version of its 470 ohm resistor.

Thanks,
- Win

(email: use hill_at_rowland-dot-org for now)
Click to expand...
YOu know, as common as this circuit is, I never messed with it - but
I've seen enough "blinkey lights" not fail. Some ran off 9V, too.

I just checked a circuit for a R/C proportional controller that uses
this same MV circuit ('cept it uses pots to vary the time constant
on one side and each pot is driven by a decade counter to get that
PPM signal - actually PWM which ends up looking like PPM.) THat
circuit uses 4k7 instead of 470 at the collectors, not that that
changes anything breakdownwise.
--
Best Regards,
Mike
 
Winfield Hill wrote:
Activ8 wrote...

But I don't recall ever seeing the circuit you to which you allude -
1 transistor, no cap. Check out:

http://www.reprise.com/host/circuits/transistor_flasher.asp


The circuit mentions 5 to 12V supplies. But if a power supply
voltage of more than about 8V is used the two transistors may
experience high reverse emitter-base breakdown current. This
causes a severe drop in the transistor's beta, which could then
cause eventual failure of the circuit. Two resistors can be
added to solve the problem. For example, connecting each 10uF
timing cap to a tapped version of its 470 ohm resistor.

Thanks,
- Win

(email: use hill_at_rowland-dot-org for now)
Click to expand...
Ehhh- that's an observation - but then you screw up the timing. The
usual technique is to drop diodes in series with the emitters.
 
On Sun, 30 May 2004 23:59:02 GMT, Fred Bloggs wrote:

Winfield Hill wrote:
Activ8 wrote...

But I don't recall ever seeing the circuit you to which you allude -
1 transistor, no cap. Check out:

http://www.reprise.com/host/circuits/transistor_flasher.asp

The circuit mentions 5 to 12V supplies. But if a power supply
voltage of more than about 8V is used the two transistors may
experience high reverse emitter-base breakdown current. This
causes a severe drop in the transistor's beta, which could then
cause eventual failure of the circuit. Two resistors can be
added to solve the problem. For example, connecting each 10uF
timing cap to a tapped version of its 470 ohm resistor.

Thanks,
- Win

(email: use hill_at_rowland-dot-org for now)


Ehhh- that's an observation - but then you screw up the timing. The
usual technique is to drop diodes in series with the emitters.
Click to expand...
Screwing up the timing is an understatement You can't move the cap
far enough from Vc to matter without killing the oscillations
altogether.
--
Best Regards,
Mike
 
daron wrote:
here is a pic
all i want to do is make 1 led flash
Click to expand...
It looks like the manufacturers have discontinued these LED-flasher
IC's. You can now just buy a flashing LED- apply power and it flashes-
also known as blinking LEDs. If you want to construct an actual circuit,
then a CMOS 555 would be the simplest, or there are bunches of LED
circuits here- that actually work:)
http://www.discovercircuits.com/L/LED.htm
 
My favorite is the LM3909 ic. I think discontinued, but some are still out
there. Small little chip (8 pins). You add a capacitor to determine the
flash rate and the LED.

Extremely long battery life. Generally, a C-cell size battery will last 1
year or longer flashing at once per second.

- - - -

"daron" <daron69@adam.com.au> wrote in message
news:1085900701.847253@teuthos...
can anyone tell me a simple way to make 1 led flash
i have a diagram for 1 led + 1 transistor + 1R
but i cant find this transistor in any shops
i have 555 timer chips but would prefer not to use them
it will be for 12 car
Click to expand...
 
Just use a flashing LED and a resistor - two components. Or go to an auto
store and get a flashing LED pre-made - a couple of bucks more but in a neat
package with a dash-mounting bezel.

Incidentally, yes, the '3909 is discontinued, and becoming hard-to-find.
Sad - a nice little device.

Ken

"Rather Play Pinball" <123@123.net> wrote in message
news:10bnja325db1o12@corp.supernews.com...
My favorite is the LM3909 ic. I think discontinued, but some are still
out
there. Small little chip (8 pins). You add a capacitor to determine the
flash rate and the LED.

Extremely long battery life. Generally, a C-cell size battery will last 1
year or longer flashing at once per second.

- - - -

"daron" <daron69@adam.com.au> wrote in message
news:1085900701.847253@teuthos...
can anyone tell me a simple way to make 1 led flash
i have a diagram for 1 led + 1 transistor + 1R
but i cant find this transistor in any shops
i have 555 timer chips but would prefer not to use them
it will be for 12 car
Click to expand...
 
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