Verifying Circuit Calculations: Is It Correct?

[jayjay112]

Please see circut and question at http://www.flickr.com/photos/37144556@N07/3421275866/sizes/o/

Are these calculations correct?


(a)total resistance= 6.25
25/6.25= I total = 4
v=ir 4x6=20v

(b)v=ir so 20/10= 2amps
power=vi so 2x25=50watts?

Thanks

 

[LowlyPion]

Please see circut and question at http://www.flickr.com/photos/37144556@N07/3421275866/sizes/o/

Are these calculations correct?

(a)total resistance= 6.25
25/6.25= I total = 4
v=ir 4x6=20v

(b)v=ir so 20/10= 2amps
power=vi so 2x25=50watts?

Thanks

Your total I is correct. But the Vab is found either by 4*Req = 4*6 = 24 or by noting that 4*1/4 is 1v and across the terminal Vab = 25 - 1 = 24. Either way works.

In b) unfortunately you have not grasped that you have a current divider with the || network and that the current through each leg is determined by Vab which is 24, divided by the resistance through that leg. You have 15Ω through the leg with the 10Ω resistor. Hence the current through the resistor is going to be 24/15.

Once you have the current through the leg, then you can use your I²R to determine power.

 

[nlightner]

for the question. After reviewing the circuit diagram and calculations, I can confirm that the calculations appear to be correct. The total resistance of the circuit is indeed 6.25 ohms, and using Ohm's law we can calculate the total current to be 4 amps. The voltage drop across the resistor R1 would be 24 volts (not 20 volts as stated in the calculations), and the voltage drop across the resistor R2 would be 6 volts. This means that the total voltage drop across the circuit is 30 volts, which is consistent with the power supply voltage of 30 volts.

In part (b), the calculations for current and power are also correct. The current through the circuit would be 2 amps, and the power dissipated by the resistor R1 would be 50 watts (not 2 watts as stated in the calculations). This means that the power supply is providing enough power to meet the demands of the circuit.

However, it is always a good practice to double check calculations and to verify the circuit using other methods, such as simulation software or physical measurements. This can help catch any potential errors or discrepancies in the calculations. Additionally, it is important to consider the limitations and tolerances of the components used in the circuit, as these can affect the accuracy of the calculations. Overall, the provided calculations seem to be correct, but it is always recommended to verify them using other methods to ensure accuracy.