Fm Transmitter for car

  Beeper Transmitter The Beep Transmitter emits a series of intermittent beeping frequency that may be easily received and picked up by any FM radio within its range.  

  Music Player Transmitter The next CD player, USB device, and mobile phone The Multimedia Transmitter sends audio signals from your PC, CD player, or smartphone to your FM audio system for playback through the system's loudspeakers without using connecting wires.

  100 meter Range Transmitter The next Two-Transistor FM Transmitter is essentially similar to the preceding design, with the exception of an additional transistor and a pair of resistor/capacitor values that have been changed to match the new circuit layout. The range of this transmitter is around 100 meters.

  150 Feet Range Transmitter The below shown One-Transistor FM Transmitter circuit's output, which can be received by any FM receiver within approximately 150 feet or less of the transmitter, provides great functionality and is suitable for wireless mic usage.

  More Transmitter Circuits The transmitter coil L1 for all the following circuits are created by hand winding 4 turns of 18 to 22 SWG super enameled copper wire over a 1 cm air cored former, using card board or plastic for the former material. The number of turns of L1 can be manually adjusted so that FM transmitter circuits are able to transmit signals within the high VHF range using 2 or 3 turns for L1, or across the lower VHF range of 50 to 80 MHz using 5 to 7 turns for L1. The variable capacitor connected parallel to the coil L1 in the all the following circuits can be a 33 pF trimmer or any FM gang capacitor.

  Circuit Description The circuit diagram for the CMOS Transmitter can be seen in the following figure. Power to the circuit is derived via B1, which is a 9 volt battery. A pair of 4011 NAND gate stages, U1c and U1d, are configured like a radio-frequency (RF) oscillator (carrier). The remaining a couple of CMOS gates, U1a and U1b, are utilized to build an audio frequency (AF) oscillator (modulator). Switch S1 helps activating an deactivating the modulation process to enable the exchange of an complex information with the Transmitter. Once the switch S1 is pressed, the AF oscillator using U1a, U1b, R4, and C1, begins producing an acoustic signal. This signal switches ON and OFF the CMOS gates U1c, U1d, R2, R3, and C2. included in the the RF oscillator stages. During the ON periods, the RF oscillator operates at 1 MHz frequency. This frequency output is delivered out to the ANT1 as an AM signal. In the switched ON position, the RF oscillator operates at 1 MHz. The fre...