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Creating magnetic field with DAQ

minqthegreat

Hello,

I'm a complete newbie in electronics but I was given an assignment to create an AC magnetic field (~30 mT max) with DAQ given (ni-usb 2681 which has analog output and can output function generator) Required current is around 1.5 Arms. I was wondering if this can be done using a solenoid, DAQ, and a power supply. What power supply would you recommend? How would you configure the circuit? Thanks in advance.

  • +1

    Tell us more - to make a good suggestion we need to know the operating frequency.

    How do you know that you need 1.5A.

    Is this a college project, can you spend any money ?

    My first suggestion would be to use an audio amplifier if the frequency range is OK.

    Probably best to avoid switching amps. There are plenty of cheap audio amps on Ebay and Amazon.

    If you wind a coil to make the field then put a resistor and capacitor in series with each other and the pair in parallel wit the coil.

    This will make the load look resistive and help the amplifier to survive -  many audio ampos do not like large inductive loads.

    To calculate  the value of the R and C you need to measure the series restance and inductance of the coil.

    MK

  • 0 in reply to michaelkellett

    Hello,

    Thank you so much for the great answer. This is a college project, where a reasonable amount of money can be spent at the expense of the university. I was looking through laboratory-grade amplifiers and they were scary expensive.

    I did a rough estimation using a formula for the magnetic field at the center of the solenoid and the value I got was ~1.8 A, more or less.

    The frequency required is around 0.5 - 5kHz, but preferably up to 25 kHz, which is a good range for an audio amplifier I believe.

    Yes, I was thinking of using a capacitor to create a resonant circuit. (That's what you meant, correct?)

    There are others who suggested using an audio amp, so, I think I will just go for that. Once again, thank you so much for the answer!

    Best regards,

    Min