Infrared Wireless Headphones circuit
Posted on Nov 10, 2015 8178
Since the transmission circuit inductive wireless headset must be fixedly mounted on a wall or ceiling of a room, it can not be
used outdoors, which is a major drawback inductive wireless headphones. The infrared wireless headset is not, due to its signal transmission uses a compact infrared transmitter circuit, both indoors and audio signals for radio reception electronic teaching, home television and audio equipment, but also the use of portable tape recorders, CD, VCD outdoors and MP3, the easily remove headset line, and truly wireless "Walkman."Infrared wireless transmission circuit of FIG earphone (a) in Fig. XP will plug into the TV when using tape recorders inside the headphone jack, the audio signal through XP via capacitive coupling Cl, transistors VTl amplification, and then launching a audio wave infrared VDl outward from the infrared emitting diode and VD2. After properly adjusting the bias resistor circuit pretend R2, flowing through VDl and VD2 quiescent current l0mA can.Figure (b) for the receiver circuit infrared wireless headphones. After the infrared receiver VD3 ~ VD5 receives infrared signals emitted from the transmitting circuit to convert it into an audio signal, and then by the transistor VT2 amplified into integrated operational amplifier ICl for power amplification, and finally by BE headphone output. Circuit using three infrared receiver is to be able to receive the full range signal. When debugging, the positive first hand touch infrared receiver tube, adjust the resistance R4, R5 output of the headset BE hum loudest, and then turned on the transmitting circuit, appropriately adjusting the volume of the TV or tape recorders size until the earpiece loud and clear so far.