AVR-Chat

If only life was so simple ....

Ralph Hilton wrote:
>>Not unless you "store" the voltage somehow. ie. you may need some 
>>diodes and capacitors. At any one time the voltage measured across the 
>>two pins is always no more than Vcc.
>>
>>Do you do advertisements for amplifiers?
> 
> Using pins 1 & 2:
> 
> Pin 1 = 0, pin2 = 5v
> then
> Pin 1 = 5v, pin2 = 0
> 
> Relative to pin1, pin2 goes from +5 volt to - 5 volt which is 10 volts peak to
> peak.

Like I said "At any one time the voltage measured across the
two pins is always no more than Vcc."

And, I maintain that unless you store some charge somewhere the 
"relative" voltage you mention is just that, an interesting point to 
note in passing.

Now, lets gets some facts going here instead of speculation ...

there are (at least) two types of "piezo buzzers"

1. A simply piezo plate that you drive directly - can be used as both 
a sound source when driven electrically and a microphone when driven 
acoustically.

2. A polarised "module" that you apply power to that has its own 
internal oscillator - the power you supply drives the buzzer "indirectly".

I agree that 1. is a candidate for being driven in antiphase. On the 
other hand 2., assuming it wont be destroyed by a reverse voltage, 
will actually run at half the voltage as only half the time will it 
have 5 Volts across it when driven as suggested.

So, You say 10 Volts peak-to-peak, and I'm saying 2.5 Volts average - 
depending on the module.





OK, I have real work to do here, sorry I brought up this whole thing. 
I'll leave it to you guys to fight out this semantic argument yourselves.

Peter.