Microphones, audio waveforms and sensor outputs are alternating current (AC) signals that contain both positive and negative half-cycles. If powered solely by a single positive supply, the negative half-cycle of the waveform will be clipped directly, leading to signal distortion. Symmetric positive and negative voltage rails enable full amplification of the complete waveform, which is an essential requirement for precision analog signal acquisition.
Application Scenarios
Audio power amplifiers, medical signal acquisition, high-precision sensors, analog front ends of oscilloscopes, Class-B audio amplifiers, and signal conditioning for precision instruments.
Key Technical Points
- Typical dual-rail power supplies: ±12 V and ±15 V;
- Without negative voltage rails, the lower half of AC signals gets truncated, causing severe degradation of the signal-to-noise ratio (SNR);
- High-fidelity audio systems must adopt low-noise negative voltage power supplies.
Further Reading on Negative Voltage Fundamentals
- Negative Voltage Basics: What Is Negative Voltage?
- Negative Voltage Basics: Voltages in Communication Circuits
- Negative Voltage Basics: Why Op-Amp & Audio Analog Circuits Require Positive/Negative Power Supplies
- Negative Voltage Basics: Charge Pump Implementations
- Negative Voltage Basics: Positive and Negative Voltage Design for Buck Circuits
- Negative Voltage Basics: Negative Rail Supply for Precision Op-Amp AC Signal Amplification