Calculating Source Voltage and Maximum Power in a Practical Circuit

In summary, the conversation is about determining the source voltage and maximum power for a practical voltage source connected to different loads. The equations for finding these values are discussed, including the equation for power (P = I^2 * R) and the equation for voltage efficiency (R / R+r). The concept of internal resistance is also mentioned, with suggestions for how to calculate it using a voltage divider.
  • #1
Kobayashi
22
0

Homework Statement


A practical voltage source has a voltage effieciency of 90% when connected to a load of 9 Ohms. When connected to a load of 4 Ohms, the load voltage was 160V. Determine the source voltage and the max power.

Can anyone help me with this question?


Homework Equations


P = (I^2)*(R)


The Attempt at a Solution


I'm not getting the correct answer.
 
Physics news on Phys.org
  • #2
Show us a little more work. A "practical" or real voltage source has an internal resistance (call it Ri) in series with an "ideal" voltage source (that has an open-circuit voltage of Vo). Write the two equations for the two load sitations given, and see if that helps you to determine what Vo is.

And once you know Vo and Ri, do you know how to choose the load resistor value to get the maximum power transfer to it?
 
  • #3
Hi, if there is a voltage effieciency of 90%: Voltage effieciency = R / R+r

Does this mean the internal resistance is equal to 1 Ohm.
 
  • #4
I honestly have no idea what "voltage efficiency" is. Is this your translation from another language? There is power efficiency, but efficiency does not pertain to voltage alone.

Maybe they mean that 0.9 * Vo = Vload?
 
  • #5
Is 1 Ohm incorrect then? How else can internal resistance be calculated in this case? That's the only way I can figure out.
 
  • #6
Kobayashi said:
Is 1 Ohm incorrect then? How else can internal resistance be calculated in this case? That's the only way I can figure out.

Well if they mean voltage divider instead of voltage efficiency, write the equation for a voltage divider to figure out what Ri is.
 

What is source voltage and why is it important?

Source voltage is the amount of electrical potential energy provided by a power source. It is important because it determines the amount of electrical current that can flow through a circuit and the maximum power that can be delivered.

What is the relationship between source voltage and max power?

The relationship between source voltage and max power is directly proportional. This means that as the source voltage increases, the maximum power that can be delivered also increases.

How is source voltage measured?

Source voltage is typically measured in volts (V) using a voltmeter. It can also be calculated by dividing the amount of electrical energy by the amount of electrical charge.

What factors can affect source voltage?

The main factors that can affect source voltage include the type of power source, the materials used in the source, and the resistance of the circuit. Changes in these factors can result in fluctuations in source voltage.

How does source voltage impact the performance of electronic devices?

Source voltage is a critical factor in the performance of electronic devices. If the source voltage is too low, the device may not function properly or at all. If the source voltage is too high, it can damage the device. It is important to ensure that the source voltage is within the recommended range for the device to function optimally.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
2
Views
721
  • Engineering and Comp Sci Homework Help
Replies
17
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
945
  • Engineering and Comp Sci Homework Help
Replies
10
Views
4K
  • Engineering and Comp Sci Homework Help
Replies
3
Views
760
  • Engineering and Comp Sci Homework Help
Replies
1
Views
233
  • Engineering and Comp Sci Homework Help
Replies
7
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
8
Views
4K
  • Engineering and Comp Sci Homework Help
Replies
6
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
8
Views
989
Back
Top