FM Wireless Mic

Description: FM Wireless Mike can transmit voice signals to any FM Radio receiver 100 meters away. The circuit is basically a frequency modulated transmitter working at 100 MHz. The frequency of the transmitter can be varied slightly by changing the trimmer C5. You can use ordinary condenser mike in this circuit. The transistors can be replaced by any low power transistors like BC148 or BF494. More: The coil L1 is air core 6 turn 24 SWG. Third turn is tapped and connected to telescopic antenna. You can replace telescopic antenna with a small piece of wire.

The FM Wireless Microphone circuit is designed to transmit audio signals wirelessly over a distance of approximately 100 meters using frequency modulation at a center frequency of 100 MHz. The circuit employs a simple yet effective design that includes key components such as a condenser microphone, low-power transistors, and an air-core coil for signal transmission.

The heart of the transmitter is the frequency modulated oscillator, which generates a carrier wave at 100 MHz. The frequency can be fine-tuned using a variable capacitor, specifically the trimmer capacitor C5. This allows for slight adjustments to the operating frequency, which is essential for avoiding interference with other radio frequency devices and ensuring optimal transmission quality.

The circuit is capable of utilizing standard condenser microphones, which convert sound waves into electrical signals. These signals are then amplified by low-power transistors, such as the BC148 or BF494, which can be substituted with other transistors of similar specifications. This flexibility in component selection makes the circuit accessible for hobbyists and engineers alike.

An important aspect of the design is the air-core coil L1, which is constructed with 6 turns of 24 SWG (standard wire gauge) wire. The third turn of the coil is tapped and connected to a telescopic antenna, which is critical for effective transmission of the modulated signal. The use of a telescopic antenna enhances the range and clarity of the transmitted audio. Alternatively, a small piece of wire can be used in place of the telescopic antenna, although this may reduce the overall transmission efficiency.

In summary, the FM Wireless Microphone circuit is a straightforward and efficient design for transmitting audio signals wirelessly. With its adjustable frequency, low-power components, and flexible antenna options, it serves as an excellent project for both educational purposes and practical applications in wireless audio transmission.FM Wireless Mike can transmit voice signals to any FM Radio receiver 100 meters away. The circuit is basically a frequency modulated transmitter working at 100 MHz. The frequency of the transmitter can be varied slightly by changing the trimmer C5. You can use ordinary condenser mike in this circuit. The transistors can be replaced by any low power transistors like BC148 or BF494. The coil L1 is air core 6 turn 24 SWG. Third turn is tapped and connected to telescopic antenna. You can replace telescopic antenna with a small piece of wire.