555 timer and Electromagnetic field (of Power!)

Thread Starter

KLillie

Joined May 31, 2014
136
Hey guys, I added the (of Power!) to make it seem more exciting. Just wondering if it was possible to create a decent emf with a square wave from a 555 timer through an inductor; decent as compared to a sine wave?
 

wayneh

Joined Sep 9, 2010
16,398
We need more information about what you're doing with the output of the timer, and what you mean by "decent emf". What's the goal? You can certainly drive a transformer with a square wave instead of a sine wave, if that's what you mean.
 

THE_RB

Joined Feb 11, 2008
5,438
I'm excited.

To answer your question we need to know that the heck "decent" means.

Decent amplitude of EMF? Decent waveshape?

(edit) Darn it - 2 minute pwned by Wayneh. :D
 

Thread Starter

KLillie

Joined May 31, 2014
136
Well I might as well spill the beans. I want to build an eddy current sensor. The square wave would have to create an emf in my air core. I was hoping to be lazy. I've been messing with oscillators, but I just bought 50 NE555 timers...It's probably a silly idea. Often doing things the lazy way becomes harder in the long run, but whadda the experts say? Oh and by decent I meant as compared to a sine wave which I imagine would work better.
 

Thread Starter

KLillie

Joined May 31, 2014
136
Think of it this way can I create an emf in an air core inductor with an ac voltage...yes. Can I do the same with a square wave?
 

takao21203

Joined Apr 28, 2012
3,695
never heard of indecent EMF which would have to exist in case it is not possible to generate decent EMF.

Seriously, it is not an issue having something to do with a NE555 or the fact you bought 50 of them.

But it governs the max. frequency, about a MHz.

So I think, first get your eddy current thing working, then consider the decency Ne555 squares vs. Sine waves.
 
Think of it this way can I create an emf in an air core inductor with an ac voltage...yes. Can I do the same with a square wave?
Textbooks state that AC is not AC unless it swings below the 0V rail. So your 555 would be producing pulsating DC.

I cannot see why your idea wouldn't work. I am very excited to see you build and demonstrate it to us on UTube.
 

Thread Starter

KLillie

Joined May 31, 2014
136
Thanks for your responses and questions! @Alpha, I like where you're going. So if I pulsed positive then negative, this could work. Now how do you pulse negative? An inverter? Is this getting into a different thread? :)
 

alfacliff

Joined Dec 13, 2013
2,458
just pass the pulses through a capacitor, then it will be bipolar. we use eddy current testers to look for paint thickness here and also for looking for cracks in airplane parts. eddy currents can be used for lots of things, what are you going to do?
 
Thanks for your responses and questions! @Alpha, I like where you're going. So if I pulsed positive then negative, this could work. Now how do you pulse negative? An inverter? Is this getting into a different thread? :)
I don't think that AC maths will be applicable. AC is the hardest part of electronics. The level of maths is something that I do not have.

Can some expert please help us with some maths?
 
The sinewave is the fundemental AC waveform. An square wave is composed of many sinewaves.

So, your pulsed waveform from the NE555 is an square wave but doesn't swing below the the 0v rail. It is DC. So how do you translate this into AC to figure out the maths?

Some expert please to help us!
 

THE_RB

Joined Feb 11, 2008
5,438
The inductance of the coil means that the current (and hence magnetic field) will not rise instantly to match a "squarewave".

If you monitor the current waveform with a series resistor and a 'scope it will give a good idea of the magnetic waveform.

Anyway the OP still has not said what this is supposed to do or how it is supposed to work.
 
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