A failed 24 V transformer in a circuit requiring an amperage of 2.5A can be replaced with a transformer rated at what minimum VA?

To determine the minimum VA rating required for the transformer to effectively support a circuit with an amperage of 2.5A, one must consider both the voltage and the current requirements of the circuit. VA (Volt-Amperes) is a unit that represents the apparent power in an AC circuit and is calculated using the formula:

VA = Voltage (in volts) × Current (in amperes).

In this scenario, the required current is 2.5A, and the voltage is 24V. By applying the formula:

VA = 24V × 2.5A = 60VA.

To ensure that the transformer can handle the load without being overloaded, it is standard practice to choose a transformer with a higher VA rating than the calculated value to allow for a margin of safety and to account for potential inrush currents and other factors.

Among the options provided, the transformer rated at 75VA not only covers the 60VA calculation but also includes this safety margin, making it the correct and most suitable choice. Selecting a transformer rated lower than 75VA, such as 40VA, 50VA, or even 54VA, would not provide sufficient capacity for the circuit's needs, risking overheating or premature failure