Ultrasonic Cleaners

Discussion in 'General Electronics Chat' started by Mad Professor, Jul 20, 2009.

  1. Mad Professor

    Thread Starter AAC Fanatic!

    Apr 15, 2009
    Good Day All.

    Me and a few mates where down the pub enjoying a few beers when somehow we got on the subject of Ultrasonic cleaners.

    Then we got on the subject of would it be possible to make your own.

    I know that ultrasonic cleaners can from anything from 15–400 kHz, most low end models are normaly 42 or 49 kHz, and from 20watts up.

    I know that the ultrasonic transducers are piezoelectric.

    so would 30volt piezo transducer driven at 42 kHz have the power to do any kind of ultrasonic cleaning.

    Thanks for your time.

    Best Regards.
  2. someonesdad

    Senior Member

    Jul 7, 2009
    Dunno; maybe someone on here has designed one. But it might be fun to take a production unit apart and make measurements on it to learn a bit about their construction and engineering.
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    The piezo transducers are probably resonant at one frequency, so selecting one that wants to run at 42KHz should give superior results.
  4. bertus


    Apr 5, 2008
  5. Mad Professor

    Thread Starter AAC Fanatic!

    Apr 15, 2009
    I do have pictures from a unit I owned some time ago, it only lasted about 6 months before the plasic casing started cracking and falling apart.

    At that time I did not own a Oscilloscope, but a DVM set to 600vac would read around 200volts ac.

    Heres a pic of the PCB: Click Me Linky

    I no longer have the unit so am unable to get any more readings or give details of parts.

    The only note I can find on my computer regarding the old unit, is a single datasheet for a BU406 Silicon NPN Switching Transistor.

    As for the piezo transducer I can get hold of 20mm to 50mm piezo's with a Resonant frequency: 42kHz ± 05kHz.
  6. Bernard


    Aug 7, 2008
    Lo freq. cleaners can tear some transistors apart, 10kHz-20kHz, 40kHZ and up seems OK, circa 1960s, but then not many 2N404's & 2N 1305's are use any more.
  7. Mad Professor

    Thread Starter AAC Fanatic!

    Apr 15, 2009
    Bernard: Thanks for the warning.

    I have picked up four 27mm piezo transducers with a resonant frequency of 42kHz, I did want the bigger ones but there out of stock.

    What is the simplest driving circuit I can build to test?

    27mm / 42kHz Piezo Transducer Specifications
    Resonant frequency: 42kHz ±05kHz
    Impedance at resonance: 500Ω
    Capacitance: 14nF ±30%
    Maximum input voltage: 30V p-p
    Operating temperature: -20C to +70C

    Thanks for your time.

    Best Regards.