# With the supply voltage and current how is this many watts possible?

#### KLillie

Joined May 31, 2014
137
With the supply voltage and current how is this many watts possible?

#### dl324

Joined Mar 30, 2015
12,871
It isn't possible. Output power can never be ≥ to the input power.

#### djsfantasi

Joined Apr 11, 2010
7,689
The output power is actually “What’s”, not “Watts”. “What’s” are a marketing term, not related to electronics

#### crutschow

Joined Mar 14, 2008
27,170
The flim-flam advertisers often use "peak" watts which are twice RMS (average real power) watts for audio signals.

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#### LowQCab

Joined Nov 6, 2012
502
Yeah,
the peak power when the internal circuitry fused into a solid mass, and caused a direct short.

#### ThePanMan

Joined Mar 13, 2020
62
I love the commercial for cell phone carriers. One of them said "Nobody has a more powerful network." And that's the truth. ALL cell phone carriers are limited to the same power. You have to be wary of HOW they say what they say. Otherwise someone's going to be selling a passenger car that can be driven with a single 9 volt transistor battery.

In short, anyone with half a brain or more should understand that under the best conditions, 12V x 3A = 36W. Under no conceivable conditions can it be any higher. Logic, physics, math - and good sense - dictates that the claim is bogus. Unless you read (or hear) it on the internet. Then you can buy cars driven with 9V batteries.

#### Audioguru again

Joined Oct 21, 2019
3,171
In addition to saying the peak (double the real) power, they say the peak power when the amplifier is turned up way too high and is causing severe clipping distortion that can double the power number again. Then they multiply by any old number.

#### LowQCab

Joined Nov 6, 2012
502
It also delivers that MASSIVE Power through puny 22-ga. wires,
that miraculously don't melt under the strain.

And then you look-up what ingredients "100%-Beef" can
"Legally" contain according to the FDA and the FTC.
They also don't mention the "other" ingredients that the "product" is "MADE-WITH".
.
.
.

Joined Jan 15, 2015
5,934
If I take 50 Watts Peak and multiply by 0.707 I get 35.35 Watts RMS. If I multiply 12 volts * 3 amps I get 36 Watts. Wow isn't coincidence wonderful. It's all about smoke and mirrors.

Ron

#### Audioguru again

Joined Oct 21, 2019
3,171
If I take 50 Watts Peak and multiply by 0.707 I get 35.35 Watts RMS. If I multiply 12 volts * 3 amps I get 36 Watts. Wow isn't coincidence wonderful. It's all about smoke and mirrors.
Ron
No. If the voltage is 1.414 times more then the current also becomes 1.414 times more. Then the power becomes 1.414 times squared= twice.

The peak power has RMS voltage of 0.707 times which causes the current to also be 0.707 times less. Then the RMS power is 0.707 squared= half.

The above example of 36W from the power supply does not say if the amplifier is almost 50% efficient using class-AB then the heating is almost 18W and each channel produces 9W RMS.

#### Tonyr1084

Joined Sep 24, 2015
5,956