Microphone, also known as An electro-acoustic equipment, is a microphone, a sound transducer converts electrical voltage is generated by sound waves to the electro-acoustic components, and then converted to electricity. For a variety of public address equipment. Microphone wide range of simple circuit.
Analysis of the microphone circuit is mainly controlled by two things: (1) signal transmission loop analysis, relatively simple analysis of various microphone input jack circuits. (2) Analysis of the microphone amplifier, microphone amplifier is a low noise audio amplifier small-signal analysis mic level control circuit is not difficult
The microphone generates an electrical signal by the motion of the magnetic field conductor. Vibrating diaphragm driven by a coil so that the coil in a magnetic field generates an induced current. Features: Firm structure, stable performance, durability, low price; the frequency characteristics of a good, in the frequency range 50-15000Hz flat amplitude-frequency characteristic curve; good point; no DC voltage, easy to use, low noise.
Characteristics, amplitude-frequency characteristic curve flat in the audio frequency range, which is better than the dynamic microphones; non-directional; high sensitivity, low noise, sound soft; the output signal level is relatively large, low distortion, good transient response, this is less than the advantage of dynamic microphones; unstable operating characteristics, low frequency sensitivity with the increase in the use of time and decline, life is short, we need to create a DC power supply is inconvenient to use at work.
There condenser microphone preamplifier, of course you have to have a power supply, due to the volume relationship, the power supply is usually placed outside the microphone.
In addition to supplying the polarization voltage of the capacitor of the diaphragm, but also for the tube or transistor preamplifier supply voltage necessary. We call it the phantom power.