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Further to my query of a flashing LED circuit not working

 

Hi there, again,
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Further to my query of a flashing LED circuit not working. From all the comments I've had, it seems as though it is a "dud" circuit, consequently I have gone to the "Plan B" circuit which I discovered when I was searching for a simple flashing circuit. This uses an NE555 timer IC. I will attach the circuit shortly in the files section. To summarise it has the 555 timer, 3 resistors - 100K ohms, 270K ohms, & 470K ohms, 1 capacitor - 1uF, and of course the Red 5mm LED. The circuit uses a 5-12VDC supply. Can I use an electrolytic 63V, 1uF or another type such as a Tantalum or a 100v Non-polarised type.?
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FWIW, I'm putting a navigation type flashing light on top of a building I'm making for my model RR layout.
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Thanks,
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Ian
 

I am also attaching to the files, a scan of the PCB solder side. Hope it is clear enough. The capacitor is located between the resistors R1 & R3.
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Ian
 

On Tue, Nov 12, 2024 at 09:07 PM, Ian Bell wrote:
Can I use an electrolytic 63V, 1uF or another type such as a Tantalum or a 100v Non-polarised type.?
I would think so - yes,? yes, and yes.
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FYI, a Tantalum capacitor is an electrolytic.? The two main kinds of electrolytic caps are Aluminum and Tantalum.
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Electrolytics may not be the world's greatest capacitor type, but should be fine in this circuit.? But be aware that most electrolytic caps have rather wide tolerances on the capacitance value, so the flash rate might differ from ideal by a little.
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The 270 K value for R3 seems awfully large.? But that value depends on the LED and the battery voltage.
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Andy
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Thank you for your reply.
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Re R3 resistor. The LED is a 5mm red one, and the input voltage is 5-12VDC, but I will be running it at 9VDC. What would you recommend if I was to replace the 270K resistor?
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Ian
 
Edited

On Wed, Nov 13, 2024 at 01:26 AM, Ian Bell wrote:
Re R3 resistor. The LED is a 5mm red one, and the input voltage is 5-12VDC, but I will be running it at 9VDC. What would you recommend if I was to replace the 270K resistor?
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I do not recommend any value.? It is for you to decide.? Read on.
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The size of the package it is in makes little if any difference.? The color makes some difference, but the key, most important things are:
  1. What is the range of rated currents for your LED?
  2. How bright do you want it to be?
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LED brightness is affected by current.? You can generally "dial down" the brightness by using less than the "rated" or maximum current for that LED.? But you should not "dial up" the current by using more.? (I have seen what happens.? If I remember correctly, the LED's cover was launched about 10 feet across the room.)
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First, look at the datasheet for the LED.? Determine what are the recommended and maximum currents.
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Then, ask yourself if you want it to have full brightness, or if you wish it to be only a soft glow and not blind you while you are trying to sleep.? If the latter, I think you will need to use trial-and-error to find what is a good current for your application.
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At 270 K ohms, the current is 33 uA or less, which strikes me as rather low for most LEDs, and it is probably more like 25 uA if you subtract a few volts for the LED and (small) voltage drop in the 555.
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Andy
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What is a FLASHING LED?? I thought it was an LED that blinked regularly as long as power was applied to it.

Based upon my (mis?) understanding, all one needed was the DC power (and, possibly a resistor) to make a flashing light.

I ask because I have been tinkering around with the idea of making a few lithium cell powered devices I could place about the property so that 'intruders' my assume there was some sort of security monitoring device about. I was hoping to employ some sort of component that turned it on after dark since, in broad daylight, it would be unlikely to fool most folks.


--
G.T.
 

On Wed, Nov 13, 2024 at 05:22 PM, Gooey wrote:
What is a FLASHING LED?? I thought it was an LED that blinked regularly as long as power was applied to it.
Correct, sort of.
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But it is not limited to LEDs designed to flash all by themselves with no external circuitry.? A "flashing LED circuit" includes a circuit designed to flash a LED.? This topic had been about a circuit that flashes an ordinary LED.? The LED flashes, but not without help of the circuit that makes it flash.
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I'm sure you can also buy LEDs that flash themselves.? All that means is that they included the other circuitry on the die (or inside the package) with the LED itself.
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Andy
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Edited

On Wed, Nov 13, 2024 at 06:11 PM, wn4isx wrote:

... But, who is going to steal a 2001 Toyota Echo or 2002 Volvo S60?

Some of those older year models are quite valuable today.? Until not long ago we had a ~2003 Toyota.? The service shop told us never to sell it.? Owners were not selling them because they knew how good they were.
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I don't pretend to know anything about different car models.
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Andy
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But who can drive a standard transmission?
I wish we Americans could still do that - that it were still possible to get cars equipped with a standard shift.
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Andy
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Ian,
The LED will not light with that 270k, change it to about 1K maybe a bit more if you want it dim.
Tony
 

My 1939 Plymouth Pickup truck is three on the floor with double clutching required. No Synchro trans.

Dan Kahn
On Wednesday, November 13, 2024 at 06:54:49 PM EST, Andy via groups.io <ai.egrps@...> wrote:


But who can drive a standard transmission?
I wish we Americans could still do that - that it were still possible to get cars equipped with a standard shift.
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Andy
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On Wed, Nov 13, 2024 at 07:28 PM, wn4isx wrote:
I've not checked but are modern US cars not available with manual transmissions?
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Don't take my word on it - but I read that stick shifts ceased to be an option on any US-sold cars a few years ago, including imports.? Bummer.
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Andy
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On Wednesday 13 November 2024 05:22:09 pm Gooey via groups.io wrote:
What is a FLASHING LED? I thought it was an LED that blinked regularly as
long as power was applied to it.

Based upon my (mis?) understanding, all one needed was the DC power (and,
possibly a resistor) to make a flashing light.
They do make those, but it's fairly trivial to make a circuit that'll flash an LED.. A couple of possibilites that come to mind are a simple astable oscillator, or a 555 astable. Probably better to use the CMOS version which willl operate to lower volages, though.

Here's another thought: You could get to the dollar store and get some of those lights with a little bitty solar panel on top. Change the LED for one of your chosen color, flashing or not, and work it over for longevity. Big Clive has some interesting thoughts about how to make them last a lot longer than they typically do, I may have posted a link not too long ago...


--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
 

On Wednesday 13 November 2024 06:54:47 pm Andy via groups.io wrote:

But who can drive a standard transmission?
I wish we Americans could still do that - that it were still possible to get cars equipped with a standard shift.
My brother won't drive anything else...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

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