Average ac values

[capt.m]

hi!

I need help about calculating the average ac values and nominal impedance of 2x100watt 8 ohm loudspeaker connected in parallel.


thanks!

[W7TFO]

To solve for the voltage here, take the square root of the Wattage times the resistance. 

2ea 100 Watt speakers = 200W.

2 ea 8 Ohm speakers (in parallel) = 4 Ohms

Solves out to 28.3 Volts

[capt.m]

thanks,

you mean to say that the total 28.3v will be the average ac value and the 4 ohm is the nominal impedance of 2x100 8 ohm loudspeaker?

so, I can calculate now the rms voltage of the transformer based on the Vav of loudspeaker.

[k4kyv]

you mean to say that the total 28.3v will be the average ac value and the 4 ohm is the nominal impedance of 2x100 8 ohm loudspeaker?

No.  The 28.3v figure is the rms voltage.  If you are talking about sine wave tones, the average value will be 0.9 X rms, or 25.5 volts, integrated over a half-cycle.  If you integrate over the entire ac cycle, the average voltage is zero.

Average power = rms voltage X rms current

so, I can calculate now the rms voltage of the transformer based on the Vav of loudspeaker.

Unless you are dealing with sinewave tones, it is impossible to  calculate, since the waveform of music and voice is completely unpredictable.

This might clear up some of the confusion regarding average power, average voltage/current and rms voltage/current.