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I am working on an ultrasonic mist maker for my school project but I can't seem to make the piezoelectric disc work and the MOSFET keeps burning up.

Can s.eone help me figure out what's wrong?

Here is the schematic (credit goes to greatscottlab on youtube.)

enter image description here

While we're at it I was wondering what would be the better power source for the circuit, a 12V DC power source or a 12V battery.

Update : I have retried the circuit the 15V is now connected at the 8-pin and no components get burned up (yay!!) but I still can't get the piezoelectric disc working. Any ideas why?

P.S. I used the 12V DC power source and I'm building it on a bread board because I do not have the necessary appliances such as solder and PCBs.

enter image description here

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  • \$\begingroup\$ What's different? Not set to 113KHz? Same piezo mist transducer? Same large toroid inductor? 1-amp adjustable supply? (Measure the 12V supply volts, your circuit might draw big amps and stop oscillating.) \$\endgroup\$
    – wbeaty
    May 22 '20 at 6:10
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    \$\begingroup\$ There's no power supply connected to NE555 power supply pin, so there's no way that schematic will work. \$\endgroup\$
    – Justme
    May 22 '20 at 8:55
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    \$\begingroup\$ I would strongly advise against trying to breadboard a high frequency, highish power circuit on a reusable breadboard. Not to say it can't be done, but you may well end up chasing problems that are caused by the physical layout, rather then inherent in the design. Take a look at electronics.stackexchange.com/questions/2103/… \$\endgroup\$
    – elchambro
    May 28 '20 at 12:07
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    \$\begingroup\$ Maybe try building it up on a single sided blank piece of PCB material deadbug style - See: edn.com/… \$\endgroup\$
    – elchambro
    May 28 '20 at 12:13
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    \$\begingroup\$ @Moonshadow if 10ohm resistor burns, then transistor is bad (gate is shorted to other pins, normally it should measure 100 meg ohms.) IRLZ44 is can be killed by "static," if humidity is not high. When FET gets killed by static, the gate shorts out, and the R2 gate resistor will burn up. Also, if R2 burns up, the 555 is probably destroyed at the same time. So, start over with new components. Try: remove the transistor, measure pin-3 of the 555, when running correctly it must show DC seven or eight volts (half of 15V.) The 15V MUST be connected to pin-8, or the 555 turns off. \$\endgroup\$
    – wbeaty
    May 28 '20 at 14:41
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According to the IRFZ44N datasheet https://www.infineon.com/dgdl/irfz44npbf.pdf?fileId=5546d462533600a40153563b3a9f220d - there is nothing in the circuit that should exceed its maximum ratings.

First thing I'd do is to check the pin orientation of the IRFZ44N - https://components101.com/mosfets/irfz44n-datasheet-pinout-features. If the source and drain are reversed, the internal zener would be forward biased and may be carrying enough current to burn up.

If D-S are not reversed:- Check for wiring errors. Replace the MOSFET and 555 and remove the 10Ohm resistor. Check that the MOSFET has stopped burning up. Still burning? - further investigate the MOSFET portion of the circuit especially for shorts to Vcc. MOSFET not burning? - check the 555 part of the circuit. When the 555 part OK, replace the 10Ohm resistor.

Welcome to Grey Smoke College - the world's best electronics teaching institution. After 60+ years, I am still an occasional student.

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