3 Volt Wireless Microphone
A circuit 3 volt wireless microphone is using a DC voltage source of 2 pieces of AA batteries so economical in its use. A circuit 3 volt wireless microphone use of microphone types elektret (condenser mic). A circuit 3 volt wireless microphone is constructed from three pieces of transistor 2N3904 and several supporting components. Wireless microphone works on an FM radio frequency range 88 MHz – 108 MHz. Schematic drawings and parts lists to make the circuit 3 volt wireless microphone can be seen in the following figure.
The circuit of 3 Volt Wireless Microphone
A circuit 3 volt wireless microphone in the image above consists of 3 main parts as follows.
Microphone amplifier section, in part serves to strengthen the audio signal from the microphone elektret (condenser microphone) that can be modulated carrier signal (carrier frequency). Microphone amplifier circuit is constructed by the configuration of the transistor Q1.
Carrier frequency generator section, this section is an oscillator that generates the carrier frequency (carrier frequency) as well as a mixer between the audio signal and a carrier wave to generate a frequency modulated by FM modulation techniques. The modulated signal is then amplified by the amplifier section FM. This oscillator circuit constructed by a circuit of transistor Q2.
FM radio amplifier section, this section serves to strengthen the modulated signal Fm from the mixer to be transmitted via a transmitting antenna. FM amplifier circuit is a voltage amplifier class C constructed by transistor Q3. The output of the amplifier section FM is an FM radio waves emitted by the antenna.
To make the circuit 3 volt wireless microphone can be made use of PCBs in the following figure.
PCB For 3 Volt Wireless Microphone
Antenna for a string 3 volt wireless microphone can be made by wire email with a length of ± 20 cm is rolled up to form an inductor.