We've recently received customer inquiries asking whether we could provide a simple and practical microphone (mic) amplifier circuit. Since we're usually not familiar with each customer's specific product design, Aoshubao generally does not provide circuit design services.
However, the simple yet functional mic preamplifier circuit shown below may offer some design inspiration. It can be widely used as the front stage in general-purpose audio amplification circuits.
If only a low amplification factor is required, the first-stage amplifier alone is often sufficient and can provide a relatively strong output gain.
The circuit operates on a 5–7V DC power supply. As long as the connections are correct, it will function normally.
Simple Mic Amplifier Circuit Diagram
This is a single-ended output circuit, suitable for low-noise and low-interference environments where extremely high SNR is not required.
However, if the application demands a high signal-to-noise ratio, a balanced output configuration is preferred. Below is a simple mic balanced output circuit. It does not include amplification, so it should be paired with an op-amp IC during implementation.
Balanced Output Mic Circuit Diagram
The circuit operates at 3–5V DC. The upper and lower resistors are typically around 2kΩ and must be closely matched for balance.
The capacitor connected in parallel across the mic terminals is a high-frequency bypass capacitor, usually in the range of 10pF to 1nF. The exact value depends on the target cutoff frequency for filtering high-frequency noise.
The output coupling capacitor is usually chosen between 0.1μF and 1μF. A larger capacitor enhances low-frequency response, while a smaller one favors high-frequency response.
Of course, this is just a basic circuit. You can expand it with additional filtering components depending on your needs to ensure cleaner signal output with less noise.
