Electret capacitive microphone
To measure the secondary coil of the output transformer,it can be measured directly with the two surface pen to check the output end of the city.If there is a certain value,the secondary coil is good,and the primary coil and the coil of the transformer are connected.
When the primary and sound coil coils of the output transformer are checked,it is necessary to disassemble the words and disconnect the primary and sound coil of the output transformer,and then measure the interruption of the primary coil and the coil coil of the output transformer.
Electret capacitive microphone
the structure and type of the electret capacitive microphone
Electret is a new type of microphone made of electret material.It has the characteristics of small size,wide band,small noise and high sensitivity.It is widely used in hearing aids,recording machines,wireless microphone and other products.
The electret microphone is composed of an acoustic electric conversion system and a field effect transistor amplifier.The common models of the domestic electret microphone are CRZ2 1,CRZ2 9,CRZ2 '15,CRZ2 66,etc.
The electret condenser microphone is composed of a capacitor equivalent to an electrode position and a junction field effect transistor amplifier.When the sound wave is transmitted,the position of the capacitor changes,which is equivalent to the change of the capacitance,while the electric quantity on the two pole of the capacitor keeps certain,then the voltage at both ends of the capacitor changes,thus the sound and electricity conversion is realized.The Junction FET amplifier amplifies the signal voltage and achieves impedance matching with the amplifier in the amplifier.
The electret capacitance type has three types: two ends and two ends. The two ended electret capacitance type has
output terminals, namely the drain and the ground end of the field effect transistor.The three terminal electret capacitance type has
output terminals,namely the drain,the source and the ground end of the field effect transistor.
Detection of electret capacitive microphone
The multimeter is placed in the RX100 gear,the black pencil case receiver's drain (D), the red surface pen receiver's source (S) and the shell (ground),and the mouthpiece to observe the instructions of the multimeter,indicating that the microphone is invalid if it is not indicated; with instructions,the microphone is normal.The greater the range of the indicator,the higher the microphone sensitivity.The detection of electret condenser microphone can be detected by the resistance meter of multimeter.For the two end electret capacitive microphone,the D end of the microphone is connected with a black pen,and the red pen is connected to the end of the ground. At this time,it is blows to the microphone with the mouth,and the pointer of the multimeter should be instructed. Compared with the same type of microphone,the larger the indication range,the higher the sensitivity of the microphone.If there is no indication,the microphone has a problem.
Wireless microphone
The structure of a wireless microphone is actually a combination of a general microphone and a wireless transmitter,operating at a frequency of 88 to 108 MHz in the FM band,they can be received by ordinary FM radio.The wireless microphone consists of a receiver,a modulation transmitting circuit,an antenna,and a battery.The sound signal is converted to the Telecom number by the sound head,and then transmitted through the modulation,and the corresponding receiver receives,amplifies and demodulates the sound amplifying device.The transmitting distance of the wireless microphone is generally less than 100m.
The detection method of wireless microphone in wireless microphone is to connect the wireless voice to a power amplifier,and use the oscilloscope dialogue to monitor the input end of Jane,when talking to Jane,the oscilloscope should have a weak audio signal, and if there is no signal,then the problem is simple.Take the words Jane apart,it is easy to see its internal structure,usually the fault caused by the coil break. Sometimes,as long as the circuit breaker is welded,the fault can be repaired.