Help needed: Making an iron tube resonate with an inductor and a microcontroller

Discussion in 'The Projects Forum' started by Thomas1983s, Jul 6, 2015.

  1. Thomas1983s

    Thread Starter New Member

    Jul 6, 2015
    Hey all,
    some help would be greatly appreciated!

    I have an iron tube which i want to make resonate using a self-wound inductor (inductor placed diametrically on the end of the tube, with some 3 mm gap between it)
    I already made it happen by connecting it to an old audio amplifier and playing a sine wave with the correct frequency.

    Resistance including the wires was 1.5 Ohm. I already thought my audio amp wouldn’t like this, but it did work. Only when the tube suddenly HIT the coil, i blew up the poor old amp :( (could this be some back EMF which made this happen?)
    The inductor has a resistance of 0.5 Ohm. I measured that i needed about 5V AC across it to make the tube resonate. For larger tubes with lower frequencies, i would probably need some more...

    Anyway, now i want to do this via an arduino.
    Idea: change a PWM signal of a certain frequency to a high power AC signal of the same frequency. It doesn’t have to be an exact sine wave, a square would also to the trick.
    I’m pondering whether it would work to use a power transistor in combination with a capacitor?

    Any help would be greatly appreciated.
    I'm looking for the simplest solution.
    And i’m also wondering if there’s any danger with what i’m doing?

  2. Thomas1983s

    Thread Starter New Member

    Jul 6, 2015
    By the way, i meant a self-wired electromagnet, of course.
    And to make more clear of what i was thinking of:
    amplyfying the PWM signal with a power transistor, then putting a capacitor in series to remove the DC bias