From: scientist77017@gmail.com   
      
   On Monday, May 20, 2019 at 10:04:35 PM UTC-5, default wrote:   
   > On Mon, 20 May 2019 18:04:36 -0700 (PDT), AK   
   >  wrote:   
   >   
   > >On Monday, May 20, 2019 at 4:48:52 PM UTC-5, default wrote:   
   > >> On Mon, 20 May 2019 12:20:32 -0700 (PDT), AK   
   > >>  wrote:   
   > >>   
   > >> >I got this, but saw no polarity markings like my other larger piezo   
   buzzer.   
   > >> >   
   > >> >Andy   
   > >> >   
   > >> >Piezo Transducer   
   > >> >Electrical Specifications:   
   > >> >   
   > >> >    Rated Voltage: 5Vp-p   
   > >> >    Rated Current: 2mA (max)   
   > >> >    Sound Output at 10cm: 85 dBA   
   > >> >    Resonant Frequency: 2.04kHz   
   > >> >    Dimensions: 8.43mm H x 12.1mm diameter   
   > >> >    Number of pins: 2   
   > >> >    Pitch: 6.5mm   
   > >> >    Lead thickness: 0.62mm   
   > >> >    PC mount   
   > >> >    Markings: 12RT04CC   
   > >>   
   > >> It is not a buzzer, it is a transducer.   
   > >>   
   > >> A transducer is a device that can convert (in this case) sound to   
   > >> electricity or electricity to sound.  To use that as a buzzer you will   
   > >> need to drive it with an oscillator, at 2.04 kilo hertz and a wave   
   > >> with a 5 volt peak to peak amplitude (to get the maximum noise out of   
   > >> it)   
   > >>   
   > >> It doesn't have the polarity indicated because it has no polarity.   
   > >> Think of it as a loudspeaker (another transducer since they can be   
   > >> used as microphones and convert sound to electricity)   
   > >>   
   > >> It will work at other frequencies with less volume.  It should click   
   > >> when you put a battery on the leads, and click again when you reverse   
   > >> the polarity of the battery.  (it also stores a charge like a   
   > >> capacitor)   
   > >>   
   > >> Look up oscillators if you want to use it as a buzzer.  The 555 makes   
   > >> a dandy oscillator.   
   > >   
   > >Ok. I want to replace the current piezo buzzer I have with something that   
   will fit on my breadboard.   
   > >   
   > >It's a pulse type which I do not like.   
   > >   
   > >Andy   
   >   
   > I like bells myself.  I cut a chime bar from some hard aluminum alloy   
   > and used a solenoid to pull down on a mallet to strike the bar.  It   
   > sounded bad (with all the mechanical noise the solenoid made) and I   
   > ended up using a 555 as a monostable timer to get just the right   
   > timing on the stroke of the mallet.   
   >   
   > I hate piezo buzzers.  Even a speaker driven with a 555 sounds better   
   > to me.   
      
   What specs do I need to look for the speaker?   
      
   My circuit runs from 9 vdc.   
      
   Andy   
      
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