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LED flasher does not work need help.

gary350

Well-Known Member
What is the life expectancy of an LED? I found another circuit that uses 330 ohm resistors instead of 470 ohm for current limiting. Then I found a 3rd circuit that uses 390 ohms. Since my 2 singled light blinkers are so hard to see in the dark and I have no more Red LEDs I stole the LEDs to build 2 more double LED flashers. 240 + 100 ohms in series = 340 ohms for current limiting. LEDs are noticeable a little bit brighter. Being brighter will probably shorten the lift of the battery. Will it shorten the life of the LED? Single LED flasher blanks so quick LED does not appear to come completely ON even with larger capacitors.

I like modern day resistors they are much more accurate than resistors were 30 years ago. I have several 1000 brand new resistors all the 470 ohm resistors meter reads 520 ohms. Nice thing about old resistors I can read the color bands. Resistors I have been buying 470 meter reads 470 most of the time yesterday I found one that read 471 on both of my meters. Bad thing about color bands on new resistors colors never look like the correct color violet always looks like back, orange looks like pink, can't tell the different between, black, brown, violet, and green looks like blue.

I have learned old electrolytic capacitors, Brand New or from on TVs all need to be tested before using them. If the value is off more than 10% off throw them in the trash. I have brand new electrolytic caps that are 30 years old, some test good and some don't. Salvaged TV parts test better than some of my American made brand new parts. I need to build a fast easy to use tester to test all the electrolytic caps so I can trash all the bad parts.
 

audioguru

Well-Known Member
Most Helpful Member
What is the life expectancy of an LED?
Cheap LEDs bought on ebay or one of the other Chinese places might last one week. Good quality LEDs say 50 thousand hours on their datasheet when operated at 20mA or less. Since LEDs gradually dim during their life then they are not used on long-life spacecraft.

I found another circuit that uses 330 ohm resistors instead of 470 ohm for current limiting. Then I found a 3rd circuit that uses 390 ohms. Since my 2 singled light blinkers are so hard to see in the dark and I have no more Red LEDs I stole the LEDs to build 2 more double LED flashers. 240 + 100 ohms in series = 340 ohms for current limiting. LEDs are noticeable a little bit brighter.
Sine our vision can see very bright things in sunlight and very dim things at night then the sensitivity of our vision is logarithmic. Double the current then the brightness is only a little more, not double. We use Ohm's Law and the fast on-off ratio to calculate the current.

Single LED flasher blinks so quick LED does not appear to come completely ON even with larger capacitors.
It blinks on and off very quickly. The current and the on-off ratio determine the brightness but because the voltage is stepped up then the current is difficult to calculate or measure.

Nice thing about old resistors I can read the color bands. Bad thing about color bands on new resistors colors never look like the correct color violet always looks like back, orange looks like pink, can't tell the different between, black, brown, violet, and green looks like blue.
Then you bought cheap Chinese resistors. My new high quality resistors have the proper colors and the values are always accurate.


I have learned old electrolytic capacitors, Brand New or from on TVs all need to be tested before using them. If the value is off more than 10% off throw them in the trash. I have brand new electrolytic caps that are 30 years old, some test good and some don't. Salvaged TV parts test better than some of my American made brand new parts. I need to build a fast easy to use tester to test all the electrolytic caps so I can trash all the bad parts.
The datasheets for electrolytic capacitors say that the accuracy is +50% to -20% or worse. I use 5% film capacitors in high impedance circuits for good accuracy.
 

shortbus=

Well-Known Member
Another thing about the LEDs that hasn't been mentioned is the light viewing angle. The older smaller LEDs are pretty bad, light only forms a small cone from many of them. This would mean the robbers have to be positioned correctly to even see them.

Crooks must be very different in Tenn. Crooks around here are more afraid of mercury or high pressure sodium lights lighting the whole area than they are of led/christmas lights in the trees.
 

gary350

Well-Known Member
Then you bought cheap Chinese resistors. My new high quality resistors have the proper colors and the values are always accurate.
The resistors that i bought at the electronic place long ago, maybe 25 years ago, before Chinese parts were being sold here look good with color bands that anyone can read but values are way off. I bought a 5000 assortment pack. I find these days Chinese parts are much better than American made parts what every the value it is always spot on. You can not knock Chinese just because it is Chinese parts are usually much better than American made. Makes no difference if chinese resistor color band can not be read resistor tape is always marked and meter tells me the value.
 

gary350

Well-Known Member
Crooks must be very different in Tenn. Crooks around here are more afraid of mercury or high pressure sodium lights lighting the whole area than they are of led/christmas lights in the trees.
I have 11 motion detector lights the whole yard lights up if something sets them off.
 

gophert

Well-Known Member
Most Helpful Member
I have 11 motion detector lights the whole yard lights up if something sets them off.
Your lights would make my yard look like a disco - I have many, many deer eating shrubs and a bunch of 6 to 12-year-old kids playing hide-n-seek (or smoking weed) in my yard at night.

Oh, how to manage my fear and ignore good judgement? Maybe I need some flashing red lights in my trees to calm myself.
 

dknguyen

Well-Known Member
Most Helpful Member
Your lights would make my yard look like a disco - I have many, many deer eating shrubs and a bunch of 6 to 12-year-old kids playing hide-n-seek (or smoking weed) in my yard at night.

Oh, how to manage my fear and ignore good judgement? Maybe I need some flashing red lights in my trees to calm myself.
There are 6 year old potheads where you live?

If you want a way to calm yourself, then by golly do the potheads have a solution for you!
 
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shortbus=

Well-Known Member
I have 11 motion detector lights the whole yard lights up if something sets them off.
Not motion detectors, just dusk to dawn lighting. By coming in a couple of times they can figure out where not to go. Still say if you just post signs saying you no longer have any lead solder, your problems are over.
 

gary350

Well-Known Member
Your lights would make my yard look like a disco - I have many, many deer eating shrubs and a bunch of 6 to 12-year-old kids playing hide-n-seek (or smoking weed) in my yard at night.

Oh, how to manage my fear and ignore good judgement? Maybe I need some flashing red lights in my trees to calm myself.
You can never be too safe especially if you live a few house from 2 guys that keep getting arrested for breaking and entering.
 

audioguru

Well-Known Member
Most Helpful Member
It is odd that your legal system allows repeat offenders. Bribery?
 

gary350

Well-Known Member
It is odd that your legal system allows repeat offenders. Bribery?
TV News says, they are letting people out of prison early, prisons are over crowded. They do shorter sentences and more probation than they use to. The boys beat the neighbor with baseball bats when they broke in looking for money neighbors spent a week in the hospital. Boys spent 1 month in jail now they are out. 5 police cars were at the boys house last week about 9pm I never heard what that was about. As long as we can keep the boys out of our yard things will be good.
 

audioguru

Well-Known Member
Most Helpful Member
Here in Canada our police are chasing the Tennesee hillbillies who snuck across the border to do their crimes here. But that makes our prisons over crowded then they build more or deport the American criminals.
When the hillbillies are not here then our police have no work to do.
 

shortbus=

Well-Known Member
It just showed that Canadians are illegally selling or smuggling more guns into the US than any other country.
 

gary350

Well-Known Member
The 10uf caps are part of the timing. 100uf caps will slow it down. Go back to 10uf caps.
I already tried 10uf they blink so fast LEDs flicker that is 10 times too fast, LEDs never seem to turn completely off. 100uf is, more better, less worser, more gooder, flash rate per LED about 2 seconds, flash rate between the 2 lights is 1 second per LED. I learned if I build flashers with 2N3904 transistors they blink slower than 2N2222 transistors.
 

audioguru

Well-Known Member
Most Helpful Member
The 47k base bias resistor values are probably too high for only a 3V supply unless the transistors have maximum current gain that is random. A 2N3904 has twice the hFE of a 2N2222.
10uF discharges in to the 47k resistor in about 0.2 seconds. 100uF takes about 2 seconds.
 

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