How it works

The definition of white noise is a random signal across all frequencies with no correlation between signal points. The majority of white noise machines on the market use either a fan or a pre-recorded repeating pattern. Babies notice these imperfections due to their sensitive hearing. Our product uses a reversed biased NPN transistor to generate a truly random signal. Let’s dive into the details.

Normally, the voltage difference between the base of an NPN and its emitter would be positive, allowing current to flow between the collector and the emitter. By reversing this voltage and holding the emitter higher than the base we create a state where the transistor is in reverse breakdown, leading to random thermal noise being generated. In this condition, the NPN transistor behaves unpredictably due to the random motion of charge carriers within the semiconductor material. This thermal noise, also known as shot noise, is inherently random and spans a wide range of frequencies, providing a natural source of white noise.

By reverse-biasing the base-emitter junction, we allow this noise to dominate the signal. The noise generated at the junction is then amplified and conditioned to ensure it maintains the characteristics of white noise—uniform power distribution across the frequency spectrum. Unlike pre-recorded or mechanical sources of white noise, this method ensures true randomness, making the generated sound more natural and free from repetitive patterns, which sensitive ears, like those of babies, can detect.

This approach leverages the fundamental principles of semiconductor physics to create a high-quality, genuinely random noise source, superior to traditional methods involving fans or audio loops.