[SOLVED] What means 1kW for a power supply ?

[kavea]

Hi guys,
What does mean 1kW power supply ? If it output impedance is 50\[\Omega\] and i connect a 50\[\Omega\] charge still i get 1kW or only a half ?

 

[ctzof]

Hi guys,
What does mean 1kW power supply ? If it output impedance is 50\[\Omega\] and i connect a 50\[\Omega\] charge still i get 1kW or only a half ?

It doesn't go like that. 1kw simply means that your power supply unit can deliver maximum 1kw of power to your system. So suppose that your system works at 10V for example, that means that with total resistance 100 ohm (50ohm +50ohm) the supply can produce a maximum current of

P=VI=>I=P/V=>10000/100=100A. If your load can work with this 100 A then you are ok, otherwise you have to find a power supply capable to produce more power. And of course the more the loads the more the current so a power supply can provide power to only a limited number of loads at the same time.

 

[kavea]

It doesn't go like that.

I have an AM emitter connected to an antenna, at constant power of 1kW

P=VI=>I=P/V=>10000/100=100A.

So, the maximum power (1kW) is delivered to both, output impedance and the load, so each of them consumpt only a half, and only 500W are delivered to the load (10A*50 ohms=500W). Is it always the case or manufacturers of power supplies double the power at the generator to give 1KW at the load ?

 

[chuckey]

For transmitters the output power will be the rated power, i.e. a 1KW transmitter will deliver 1 KW to its rated load (normally 50 ohms). The actual power consumption of the transmitter will be greater, could be +5% for a class D MW transmitter to + 1200% for a valve TV transmitter.
Frank

 

[FvM]

Power supply operation isn't based on impedance matching.

 

[kavea]

For transmitters the output power will be the rated power, i.e. a 1KW transmitter will deliver 1 KW to its rated load (normally 50 ohms). The actual power consumption of the transmitter will be greater, could be +5% for a class D MW transmitter to + 1200% for a valve TV transmitter.
Frank

Thanks Frank! That what i looked for