40 Hz LED

[Flashthelight]

Hi All, Im brand new here and have limited knowledge in the field of electronics. My question is: how would I go about getting an LED to flash at 40 Hz?

Thanks!
-FTL

 

[davenn]

Hi
welcome to EP

Hi All, Im brand new here and have limited knowledge in the field of electronics. My question is: how would I go about getting an LED to flash at 40 Hz?

Thanks!
-FTL

put it on the output of a 40Hz oscillator using a 555 timer
there are dozens of 555 timer circuits and tutorials on the net

come back after doing some research if you have any other questions


Dave

 

[cjdelphi]

At 40hz you could exploit a 2n2222 transistor and a capacitor to do it

 

[BobK]

At 40hz you could exploit a 2n2222 transistor and a capacitor to do it

I'd like to see that circuit.

Bob

 

[BobK]

Oh, maybe you are talking about using the Vbe breakdown voltage to make a relaxation oscillator?

As Steve showed in a major research project, this will destroy the transistor eventually.

Bob

 

[cjdelphi]

Oh, maybe you are talking about using the Vbe breakdown voltage to make a relaxation oscillator?

As Steve showed in a major research project, this will destroy the transistor eventually.

Bob

I am, however the 2n2222 costs around 0.02c?

Do you happen to know what kind of life span it will get? - I'll perfboard one up and stick it in the corner somewhere and wait, and wait....

 

[BobK]

That would be interesting to see. It will probably work for quite a long time. Steve's research just showed that the beta deteriorated when exposed to repeated breakdowns, but that might not matter for the relaxation oscillator.

Bob

 

[(*steve*)]

A pair of 2N2222's configured as an astable multivibrator would be an option I'd consider.

Also I'm a bit uncomfortable with my quick experiment being called a major research project

 

[cjdelphi]

I'd like to see that circuit.

Bob

The only real down side is the high voltage required to break that reverse breakdown barrier, if it worked with say 2 or 3v that would be nice, i'll breadboard it and do a circuit for around 40hz tomorrow

 

[BobK]

Also I'm a bit uncomfortable with my quick experiment being called a major research project

Hey, if you look at some of the research that gets funded... I'm just sayin'

Bob

 

[Doug3004]

If I had to get a LED to blink at exactly 40 Hz, I would use an Arduino Nano clone to control it.

That may seem like overkill, but the Chinese Nano clones only cost $3 shipped w/USB cable if you are in the USA.
The Nano would be accurate to within (roughly) 4/1,000,000ths of a second; no analog circuit you could build for the same price would do nearly as well.
Plus you can alter the blink frequency just by changing a numeric value in a line of computer code.

If you want to construct a circuit on your own just because you want to do it, then just put "circuit to blink LED" into Google and stand back.
Many use a 555 chip, but many don't--and you can build a circuit to mimic the 555 chip if you want.
But none of these is going to be cheaper, faster or more accurate than just using the Arduino Nano.

 

[Herschel Peeler]

For others who might follow this thread later,,,,