 White noise is defined as a random signal having equal intensity at different frequencies. It's used for audio engineering, generating random numbers, and of course, sound synthesis. It's easy to generate white noise using a simple circuit that sort of misuses a transistor. By reverse biasing this NPN transistor, we're essentially pushing current through the opposite way it was intended to flow. To do this, the reverse voltage needs to go above a threshold of 6 volts. Then the noise is generated and amplified by that second transistor, and it sounds like this.