Amplifier Circuit DiagramsAudio Circuit Diagrams

Low-Noise Microphone Amplifier Schematic Circuit Diagram

The signal from a microphone is two weak for a standard line input. This low-noise DC-coupled microphone amplifier provides a solution for anyone who wants to connect a microphone to his or her hi-fi installation. As can be seen from the schematic diagram, a good circuit does not have to be complex. A differential amplifier is built around T1 (MAT-03E), which is a low-noise dual transistor. The combination of T2 and LED D1 forms a constant-current source for the input stage.

Low-Noise Microphone Amplifier Schematic Circuit DiagramA low-noise opamp (OP-270E) amplifies the difference signal that appears at the collectors of the dual transistor. The result is an analog signal at the line level. The bandwidth of the amplifier ranges from 1 Hz to 20 kHz. Within the audio range (20 Hz to 20 kHz), the distortion is less than 0.005 percent. Since only half of the OP-270E is used, the remaining opamp could be used in the output stage of a stereo version. The amplifier can be powered from a stabilized, symmetrical supply with a voltage between ±12 V and ±15 V. Such supply voltages are already present in many amplifiers.

An operational amplifier is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op-amp produces an output potential that is typically 100,000 times larger than the potential difference between its input terminals.
In the most basic circuit, op-amps are used as voltage amplifiers, which can be broadly divided into noninverting and inverting amplifiers. Voltage followers (also simply called buffers) are a type of commonly used noninverting amplifiers. Op-amps are also used as differential amplifiers, integrator circuits, etc. An operational amplifier (op-amp) is an integrated circuit (IC) that amplifies the difference in voltage between two inputs. It is so named because it can be configured to perform arithmetic operations. A common op-amp circuit uses a feedback capacitor to limit the bandwidth. Limiting op-amp bandwidth will reduce noise, so a feedback capacitor is a common way to reduce noise.
Tags

Related Articles

Leave a Reply

Your email address will not be published.

Back to top button
Close
Close