Electronics Engineering (ELEX) Board Practice Exam

What do you call the ratio of voltage transform at the first port to the current transform at the second port?

1. Transfer impedance

2. Transfer function

3. Voltage gain

4. Current transfer

The correct answer is: Transfer impedance

The ratio of voltage transform at the first port to the current transform at the second port is known as transfer impedance. This concept is essential in the analysis of linear electrical networks, especially in situations where the relationship between voltage and current is being investigated across different ports of a network or device. Transfer impedance is defined as the complex ratio of voltage at one port to the current at another port. Mathematically, it can be written as Z_T = V_1/I_2, where V_1 is the voltage measured at the first port and I_2 is the current measured at the second port. This parameter is particularly useful in describing how signals propagate through a network and can significantly affect the overall performance of circuits, such as in amplifiers, filters, and various RF (radio frequency) applications. On the other hand, the other choices describe different concepts. The transfer function relates the output of a system to its input in the Laplace domain, while voltage gain refers specifically to the increase in voltage amplitude from input to output. Current transfer would imply a specific focus on current, rather than a combined ratio of voltage and current, thus it does not accurately describe the relationship in question.