Voltage and current calculation on a mixed circuit

In summary, the problem involves a circuit with several resistors and a voltage source. The task is to calculate the voltage and current across each resistor when the switch is open and closed. To solve this problem, the concept of resistors in parallel and series is used, along with the equation V=IR. When the switch is open, the current and voltage can be easily calculated using the values of the resistors. When the switch is closed, the problem becomes more complex and the use of Delta-Wye transformations and KCL equations is necessary to find the unknown values.
  • #1
sylvarant
5
0

Homework Statement


I have the following circuit
http://informatici.vankeer.eu/files/2/Untitled.png

R1 = 22 ohm, R2 = 39, R3 = 82, R4 = 100,R5 = 10
and V = 2volt

I'm asked to calculate the voltage and current over de resistors

when the switch is open and when the switch is closed

Homework Equations


when 2 resistors form a combination the current is the same and V = IR

when 2 resistors are in parallell there voltages are the same and Ii = V/Ri


The Attempt at a Solution


well when the switch is open I obtain the following
the resistors R1 and R4 form a combination and so do R2 and R3 the voltage remains equal for both combinations so we can easily calculate the current
I1=I4 = 2v/(22+100)ohm = 0.016 A
now we find the voltage over both resistors
V1= 0.016 * 22 = 0.361 Volt
v4 = 0.016 * 100
Same way for I2 and I3

But I'm stuck when the switch is closed how do I calculate the current and voltage then ?
 
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  • #2
It might be well to read up on "Delta-Wye" transformations.
 
  • #3
sylvarant said:
But I'm stuck when the switch is closed how do I calculate the current and voltage then ?


Have you learned how to write KCL equations yet? Write the two KCL equations for the left and right nodes, and solve for the two unknowns V(left node) and V(right node).
 

1. What is the difference between voltage and current?

Voltage is the electrical potential difference between two points in a circuit, while current is the flow of electric charge through a circuit. Voltage is measured in volts (V) and current is measured in amperes (A).

2. How do you calculate total resistance in a mixed circuit?

To calculate total resistance in a mixed circuit, you must first calculate the individual resistances of each component in the circuit. Then, use the formula R(total) = R1 + R2 + R3 +... where R is the resistance of each component. This will give you the total resistance of the circuit.

3. How do you calculate voltage in a mixed circuit?

To calculate voltage in a mixed circuit, you can use Ohm's Law which states that voltage (V) is equal to current (I) multiplied by resistance (R). So, V = I x R. You can also use Kirchhoff's Voltage Law, which states that the sum of all voltages in a closed loop in a circuit is equal to zero.

4. How do you calculate current in a mixed circuit?

To calculate current in a mixed circuit, you can use Ohm's Law which states that current (I) is equal to voltage (V) divided by resistance (R). So, I = V/R. You can also use Kirchhoff's Current Law, which states that the sum of all currents entering a node in a circuit is equal to the sum of all currents exiting the node.

5. What are the advantages of using a mixed circuit over a series or parallel circuit?

A mixed circuit offers the advantage of being able to handle different types of components (e.g. resistors, capacitors, inductors) in the same circuit. This allows for more flexibility in designing and building circuits. Additionally, mixed circuits can have the benefits of both series and parallel circuits, such as providing different voltage levels and allowing for independent control of different components.

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