What shape of magnetic field are you looking for? How you arrange the poles produces very different results.

Shape of magnetic field

Bob

the magnetic field produces it with a solenoid quondi an electromagnet in which the field flows from the inside to the outside and if the current flowing through the wire is continuous the magnetic field is static and if the current is alternating electromagnetic induction is produced which if I'm not mistaken is an electromagnetic field

 

So, just wind a solenoid and put current (DC or AC) through it. What is the question?

Bob

 

Is this for a medical device? Some sort of TMS treatment for depression or other psychological illness?

 

So, just wind a solenoid and put current (DC or AC) through it. What is the question?

Bob

how can i make this magnetic field pulsate?

 

Is this for a medical device? Some sort of TMS treatment for depression or other psychological illness?

no djfantasi the medical purpose has nothing to do with it

 

So, just wind a solenoid and put current (DC or AC) through it. What is the question?

Bob

So, just wind a solenoid and put current (DC or AC) through it. What is the question?

Bob

the problem is that alternating current makes magnetic and electric fields "couple" and produces electromagnetic field that's why it insists on pulsed direct current, and I have found that it is used in welding machines and stepper motors. The operating principle is to couple a square wave to a direct current through a PWM modulation, and in detail they use a MOSFET transitor to switch on and off

 

Turning a coil on and off with DC produces electromagnetic waves just like a sine wave would.

I still have no idea about what you are trying to accomplish.

Bob

 

Turning a coil on and off with DC produces electromagnetic waves just like a sine wave would.

I still have no idea about what you are trying to accomplish.

Bob

what I want to realize is a pulsed direct current, used for example in stepper motors. So I read that you have to use a PWM pulse modulation, and then use a MOSFET transistor to switch the DC current on and off. In this case the correct being continuous has only one polarity, and if there are problems a diode is inserted to rectify it, but we always use direct current so there is no polarity exchange

 

Stop telling us about the circuit think you need and the incorrect assumptions that led to it.

Tell us what you want the results to be and what you will do with it.

You can buy a PWM controller for almost mothing, and connect it to a coil, but what will you do when you have that?

Bob

 

Stop telling us about the circuit think you need and the incorrect assumptions that led to it.

Tell us what you want the results to be and what you will do with it.

You can buy a PWM controller for almost mothing, and connect it to a coil, but what will you do when you have that?

Bob

ok by connecting it to the DC powered coil with an internal ferrite core, I get an electromagnet that mj produces a pulsed static (non-variable) magnetic field, i.e. simply turn on and off

 

Stop telling us about the circuit think you need and the incorrect assumptions that led to it.

Tell us what you want the results to be and what you will do with it.

You can buy a PWM controller for almost mothing, and connect it to a coil, but what will you do when you have that?

Bob

for the electromagnetic field I think I use simple EMPs where the tutorials can be found on the internet or youtube. However, in your opinion regarding the pulsed static magnetic field, is the idea of using a PWM with a transistor okay?

 

ok by connecting it to the DC powered coil with an internal ferrite core, I get an electromagnet that mj produces a pulsed static (non-variable) magnetic field, i.e. simply turn on and off

This is not possible. A pulsed static (non-variable) magnetic field is a contradiction. That is not how it works.

 

This is not possible. A pulsed static (non-variable) magnetic field is a contradiction. That is not how it works.

and then how do I create a pulsed magnetic field, I mean in the simplest sense that is to turn on and off for example 100 times a second, now there and after it is gone. By static we mean, created by a DC, and with a PWM turn on and off, I'm failing to understand why that's not possible. Obviously the PWM will be managed digitally as well as the number of pulses

 

and then how do I create a pulsed magnetic field, I mean in the simplest sense that is to turn on and off for example 100 times a second, now there and after it is gone. By static we mean, created by a DC, and with a PWM turn on and off, I'm failing to understand why that's not possible. Obviously the PWM will be managed digitally as well as the number of pulses

A pulsed magnetic field is created by applying and removing a DC current. If the pulses are smooth then the magnetic field will rise and fall accordingly. If the pulses are square you will get an entirely different behavior with large voltage spikes at the turnoff. Theses spikes can and will damage any switching device that you may choose to use. If you do not saturate the core, then the magnetic field strength will be proportional to the current, and the voltage across the inductor will be proportional to the derivative of the current with respect to time.

 

A pulsed magnetic field is created by applying and removing a DC current. If the pulses are smooth then the magnetic field will rise and fall accordingly. If the pulses are square you will get an entirely different behavior with large voltage spikes at the turnoff. Theses spikes can and will damage any switching device that you may choose to use. If you do not saturate the core, then the magnetic field strength will be proportional to the current, and the voltage across the inductor will be proportional to the derivative of the current with respect to time.

ok in this I do not scorn and I follow your advice, so since the PWM uses square waves, to create "smooth" waves as you said in the first part of the answer, how can I do?

 

How about a sinewave with a DC offset equal to the peak voltage of the AC waveform. Something like:

\( 10\;+\;10sin(2\pi ft) \)

for some frequency
\( f \)

 

Sorry, I cannot help you when you won’t tell me what it us you are trying to do.

This is an example of what I need you to tell me:

“I want to create a pulsed magnetic field of 200 Gauss in a cylindrical volume 2cm in diameter an 1 cm in height. The pulses will have a frequency adjustable from 1 to 3 KHz with a duty cycle of 10% to 50% and rise and fall times of less than 50us. I will use this to study the effect of a pulsed magnetic field on bacteria growth.”

With that kind of explanation, we could start exploring possible solutions.

Bob

 

for the electromagnetic field I think I use simple EMPs where the tutorials can be found on the internet or youtube.

Do you know what EMP refers to?

EMP

Is that what you are trying to do?

Bob

 

To my naive mind, it sounds like he is after a way to make a TMS without having to say it out loud. There have been a few threads over the last year or so that when the thread starter actually said it, the thread gets shut down. so I'm thinking he won't say TMS to keep the thread from being locked. Just my opinion.
https://en.wikipedia.org/wiki/Transcranial_magnetic_stimulation

 

Then he probably shouldn’t be saying EMP either .

Bob