The LM3909 was designed to simply blink and do it for a long time. Simple design and used extensively in the construction industry for warning markers. This surprises me as to why it is not a relatively inexpensive chip compared to it's more complicated NE555 brother. Has to be the sheer number of relative timers sold.
Blinking LED's
- Thread starter Hobby Bob
- Start date
Thanks for the above, I can follow the layout, how do you adjust the frequency of the flash ?
That is hearing aids on!
When you get fitted with your hearing aids, make sure you get the one with the wife mute button!
Yep, used to work with a guy who had the old cigarette pack hearing aid, which he would often turn off when he was involved in something.
As to LM3909 timing, check the PDF https://www.alldatasheet.com/datasheet-pdf/pdf/8895/NSC/LM3909.html t=1/f
As to LM3909 timing, check the PDF https://www.alldatasheet.com/datasheet-pdf/pdf/8895/NSC/LM3909.html t=1/f
Thanks for the link Sam, I'll print it off...
djsfantasi
- Joined Apr 11, 2010
- 9,163
One flash every 5 seconds is 0.2Hz.
Hertz is pulses per second. 1 Hz is one pulse per second. 5 Hz is five pulses per second. So 1 pulse / 5 seconds is 0.2 Hz.
THANKS for that, mystery solved !!!
Note how everyone else is using Hz, not hz.
In electrical engineering, and many other disciplines, capitalization and attention to detail are important.
Take for example 1MW and 1mW; one is a billion times larger than the other.
Understood, thanks for the pointer on that, wouldn't be much good building a 1000 mw power station then hey
Every once in awhile, someone mentions using a 1MF capacitor when they probably meant 1uF (the usage of mF to mean microfarads went out of style long ago, but it still manages to cause confusion).Understood, thanks for the pointer on that, wouldn't be much good building a 1000 mw power station then hey
Audioguru again
- Joined Oct 21, 2019
- 6,691
My hearing aids have front mics and rear mics. In setting #1 it switches on only the mics that have the loudest speech.
The hearing aids also have 4 settings from a pushbutton on top of either one:
1) Normal gain but has compression of loud sounds and has automatic noise reduction that slowly fades noise away.
2) Normal gain but compression is turned off and noise reduction is turned off for music.
3) Extra sensitivity so I can snoop at what faint and distant people are saying.
4) Muting so I do not hear nagging.
It also automatically senses a telephone and switches so that I hear the phone in both ears.
It warns me when the 10 days old batteries are low.
The hearing aids also have 4 settings from a pushbutton on top of either one:
1) Normal gain but has compression of loud sounds and has automatic noise reduction that slowly fades noise away.
2) Normal gain but compression is turned off and noise reduction is turned off for music.
3) Extra sensitivity so I can snoop at what faint and distant people are saying.
4) Muting so I do not hear nagging.
It also automatically senses a telephone and switches so that I hear the phone in both ears.
It warns me when the 10 days old batteries are low.
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