Magnetically Coupled Circuits

What physical phenomenon is the basis for mutual inductance in coupled circuits?

What is the primary purpose of the dot convention in the analysis of magnetically coupled coils?

According to the dot convention, if a current enters the dotted terminal of coil 1, where is the positive voltage reference for the open-circuit voltage produced in coil 2?

What is the physical basis for the placement of dots in the dot convention?

What is the relationship that defines the upper limit for the mutual inductance M between two coils with self-inductances L1 and L2?

The coupling coefficient, k, provides a measure of the degree of magnetic coupling between two coils. What is the possible range of values for k?

What is the correct expression for the total energy stored in a pair of coupled coils if the currents i1 and i2 both enter their respective dot-marked terminals?

A linear transformer has primary and secondary windings. What is meant by the term 'reflected impedance'?

What are the two key characteristics that define an 'ideal transformer'?

For an ideal transformer with a turns ratio 'a' (defined as N2/N1), what is the relationship between the primary voltage V1 and the secondary voltage V2?

For an ideal transformer with a turns ratio 'a' (defined as N2/N1), what is the relationship between the primary current I1 and the secondary current I2?

How is the input impedance Zin seen at the primary of an ideal transformer related to the load impedance ZL connected to the secondary, given a turns ratio 'a' (N2/N1)?

A transformer that increases the voltage from primary to secondary (V2 > V1) is known as what type of transformer?

How can a linear transformer be represented by an equivalent network of inductors without any mutual inductance?

What might be a consequence of using the T-equivalent network to model a linear transformer?

Two coils have self-inductances of L1 = 10 H and L2 = 40 H. What is the maximum possible value for the mutual inductance M between them?

A pair of coupled coils has L1 = 0.4 H, L2 = 2.5 H, and a coupling coefficient k = 0.6. What is the mutual inductance M?

In the T-equivalent network for a linear transformer with inductances L1, L2, and M, what are the inductances of the three branches of the T model, assuming the dots are placed such that M is positive?

An ideal transformer is used for impedance matching. A source with an internal impedance of 4000 ohms needs to be matched to a speaker with an impedance of 8 ohms. What should the turns ratio a (N1/N2) be?

An ideal transformer has a primary voltage V1 of 50 V rms and a turns ratio a (N2/N1) of 10. If a 10 k-ohm resistor is connected to the secondary, what is the current I1 in the primary?

In the context of a linear transformer, how does the reactance reflected from the secondary circuit into the primary circuit behave?

The power rating of a large transformer is typically given in what units?

A linear transformer with M = 15 mH has dots on opposite ends of the primary and secondary windings. What is the equivalent value of M to be used in the T-equivalent network calculation?

What is the primary motivation for using step-up transformers in long-distance power transmission?

An ideal transformer has 1000 turns on the primary (N1) and 5000 turns on the secondary (N2). What is its turns ratio 'a'?

For a linear transformer with L1 = 30 mH, L2 = 60 mH, and M = 40 mH, what is the inductance of the upper left arm in its T-equivalent network?

If two coils are described as 'tightly coupled', what does this imply about their coupling coefficient k?

When modeling an ideal transformer, what happens to the power transferred from the primary to the secondary?

A linear transformer is constructed without a magnetic core. What is a typical range for its coupling coefficient?

An ideal transformer has a turns ratio `a = 0.1`. If a 50 ohm resistive load is connected to the secondary, what is the input impedance seen at the primary?

If a linear transformer has L1 = 1 H, L2 = 9 H, and M = 2 H, with a standard dot configuration, what is the inductance of the center branch in the T-equivalent model?

An ideal transformer has a primary current of 2 A rms. If the turns ratio N1:N2 is 4:1, what is the secondary current?

The voltage induced in one coil due to the time rate of change of current in a second coil is defined by what parameter?

In the T-equivalent of a linear transformer where the dots are on opposite ends of the windings (subtractive coupling), how are the branch inductances calculated from L1, L2, and M?

When is the Thévenin equivalent circuit particularly useful in analyzing circuits with ideal transformers?

An ideal transformer has a turns ratio `a = N2/N1` of 2. A voltage source Vs = 10 V rms is connected to the primary through a series impedance Zg1 = 50 ohms. What is the Thévenin equivalent voltage seen looking into the secondary terminals?

Following the previous question, an ideal transformer has a turns ratio a = 2. A voltage source Vs is connected to the primary through a series impedance Zg1 = 50 ohms. What is the Thévenin equivalent impedance seen looking into the secondary terminals?

The self-inductance of a coil is proportional to what property of its construction?

If a pair of coupled coils has L1 = 5 mH and L2 = 20 mH, and the coupling coefficient k=0.5, what is the mutual inductance M?

In a linear transformer circuit, the primary mesh contains the source and is called the primary. What is the mesh containing the load called?

A linear transformer has L1 = 20 mH, L2 = 50 mH, and M = 10 mH. If the dots are placed such that the coupling is subtractive, what is the inductance of the primary-side arm in the T-equivalent network?

When analyzing the total energy stored in coupled coils, if one current enters a dot and the other current also enters a dot, what is the sign of the mutual energy term (M*i1*i2)?

The relationship L2/L1 = a^2 for an ideal transformer is a direct result of what physical property?

In a circuit with two coupled coils, the mutual inductance is M = 3 H. A current i1(t) = 4sin(50t) A flows in the first coil. According to the dot convention, the induced voltage in the second coil is v2(t) = -M di1/dt. What is v2(t)?

A linear transformer has inductances L1 = 1H, L2= 1H, and a coupling coefficient k=0.8. What is the value of the mutual inductance M?

What does a turns ratio `a` less than 1 signify for an ideal transformer?

To correctly use the T-equivalent network for a transformer in mesh analysis, where must the lower terminals of the primary and secondary be connected?

An ideal transformer has 200 primary turns and 50 secondary turns. If the primary voltage is 120 V rms, what is the secondary voltage?

If you need to replace a T network of inductors with a linear transformer, and one of the T network inductors has a negative value, what does this imply?

In the context of the reflected impedance Zin = Z11 + omega^2*M^2/Z22 for a linear transformer, what does Z22 represent?