Back to repelling bats

[audioguru]

These tiny amplifier ICs fry when their supply is as high as 12V and they drive an 8 ohm speaker. You must calculate their amount of heating when they drive a piezo transducer. The capacitance of the piezo and the frequency are entered into the heating calculation.

 

[MrDEB]

the piezo horn tweeter I am using is a PYLE PRO PSN1167
SPL=93db@1W/1M
impedance appears as .12uf capacitor
200wattsrms/400watts peak
4-8 ohm impedance applications
a 30 ohm series resistor recommended to assure stability of extended range amplifiers preclude hazard of amplifier burn-out
I realize these are not high quality but the birds could care less.
As for the bats, IMO I don't think the ultra sonic sound frequency bothers them but it must screw up their ability to hone in on prey so why stick around. this is my theory.
The battery pack is not cemented in stone yet so anything from 7v up will do. the 7v is so the LDO regulator will work. 12v is perhaps the desired battery pak taking into consideration battery drain and cold weather conditions.

 

[audioguru]

The impedance of the 0.12uF piezo tweeter at 30kHz is 44 ohms. If you add a 12 ohm series resistor then the total impedance is 56 ohms, the power from a bridged amplifier operating from a 9V supply is 0.76W and the effective amplifier power to an 8 ohm tweeter is 5.3W. The numbers account for the square-wave signal that has double the power of a sine-wave with the same peak voltage.

 

[MrDEB]

Just plug along with the TDA2822 8 pin package or ?
amazing how you compute all them figures. Wish I understood the math but I am perhaps the least competent person for understanding anything other than add, subtract, multiply, divide whole numbers.
get some decimal points I am lost.

 

[audioguru]

I think you should use a TDA2822M which is in an 8-pins DIL package as a bridged amplifier.
A TDA2822D is in a tiny surface-mount package and might overheat.