ET Value
ET Value Requirements in Transformer Design:
In electronic transformer design, there is an important value that is often overlooked due to the difficulty in testing it: the volt-second characteristic, also known as the ET value. The ET value represents the product of the amplitude (E) and duration (T) of the pulse signal applied to the primary winding of the transformer. The ET product is typically measured in volt-microseconds (V-µs).
• E-T: Voltage-time minimum rating (Unit: V-µs)
• B: Maximum allowable magnetic flux density
• Ae: Effective cross-sectional area of the core
Under the condition that the volt-second capacity of a switching transformer is fixed, the higher the input voltage, the shorter the time the transformer can withstand the pulse. Conversely, the lower the input voltage, the longer the transformer can withstand the pulse. Additionally, under a fixed operating voltage, the larger the volt-second capacity of the switching transformer, the lower the magnetic flux density in the transformer core, making it less likely for the core to become saturated.